A Bit About Dental Photography

[Ahmadkawi]

I decided to write this to help anyone interested in the subject. My first and most important resource for information is Wolfgang Bengel’s book; Mastering Dental Photography. It’s an awesome book that goes into detail in everything.

http://www.amazon.com/Mastering-Digital-Dental-Photography-Wolfgang/dp/1850971528

Apart from that, I learned a great deal when I came to buy my first D-SLR. And the point of me writing this, is to perhaps give some people a sort of heads-up before they buy anything. I currently own a Nikon D3200 which is what I could afford at the time, and I didn’t strictly buy it for dental photography, but for general photography “which is becoming a serious hobby along with guitars and books”. So you’ll have to excuse the Nikon references, but the core technical stuff applies to all brands.

Basic Setup and Why:

The idea basic setup is having a D-SLR with a macro lens and twin flash. Someone would ask why a D-SLR and all that stuff? Why not a point-and-shoot? Or my expensive iphone? Well, because they suck.

You mainly need a macro lens because you need to close-up for a 1:1 reproduction ratio or to close-up anyway without everything going out of perspective. That’s the sort of thing when you take a close-up of your wife and her nose looks as big as a fish and then she whines that she looks ugly in the photograph. Point-and-shoots usually come with lenses that have a short focal length. The focal length is the distance between the lens and the sensor. For more thorough information, check the following link.

http://www.nikonusa.com/en/Learn-And-Explore/Article/g3cu6o2o/understanding-focal-length.html

As a rule, the longer the focal length the more things look normal in perspective. Which makes the 85mm a staple portrait lens, or good for everything lens. So, having things in good perspective is awesome, but the minimum focusing distance for a lens like that would be too far to get a close-up shot of that central incisor you want to match. You need a macro lens for that so you can close-up. With a macro-lens you can close-up and register the object you want at a 1:1 reproduction ration. The image on the senor is the same size as the actual object. Check link below.

http://www.nikonusa.com/en/Learn-And-Explore/Article/gnhy8b3m/macro-lenses.html

You’ll see that the Nikon lenses have a distance at which they give a 1:1 image. However, those numbers aren’t true. I own the 40mm Micro-Nikkor, and I have to get really close to the object I’m shooting to get that 1:1. Is that a problem? Yes. Because you need to use light to illuminate the subject, and when the camera is that close to the subject, there’s very little light coming from the side, even if you’re using twin flash. So what do you do? You use a macro lens that allows you get 1:1 from a distance, which after reading and experimenting “with a ruler” places the 105mm Micro-Nikkor as the perfect lens.

For a comparative review on the 40mm, 85 and 105mm check the following link.

http://www.cameralabs.com/reviews/Nikon_Nikkor_Macro_Micro_lens_comparison/

So now that you have to use this 105mm macro lens, whether it’s by Nikon or Canon or Acme’s Devil Brand, you need to have a D-SLR, because you need a good camera that allows you to change lenses. So that’s that.

About Flash

As for the flash, regular camera speedlight units are not suitable for use. Dental photography is macro photography, unless you’re shooting portraits of the patients. And macro photography requires a macro flash which is either a ring flash or a twin flash. Why you might ask. Because a speedlight unit mounted on the camera’s hotshoe, is sort of distant from the subject and too harsh for lighting the subject. Instead you need light that’s closer to the lens and the subject.

There’s ring light, which is continuous light. That’s silly don’t by that. Which leaves you with ring flash and twin flash. Ring flash is cool, but they often say that it’s not perfect because it leaves circular halos on the subject, especially teeth being reflective and all, and it tends to flatten out the subject. Then again, I’ve seen a picture of Olivier Tric using it. They recommend using a twin flash. That’s what they have where I work and it’s just great. Especially if you have a good one, that allows you to adjust the power of the speedlight units.

Important Tip: some flashes can be controlled wirelessly. For instance Nikon has the R1 twin flash and the R1C1 twin flash. The difference is that the R1 is mainly the two speedlight units and they’re controlled wirelessly by the commander flash, which is the camera built-in flash. In some cameras the built-in flash, or the camera itself has a commander function to control a flash unit or several ones wirelessly. Unfortunately, some cameras don’t have a commander function and hence, will have to use the R1C1 which comes with a commander unit. Yep, that’s about a $300 difference in price.

So buy a camera with a commander mode. If it’s a Nikon. If it’s not a Nikon, well you get the idea.

Full frame and APS-C Frame sensors

My camera has a DX sensor. That’s what Nikon calls it. it’s actually and APS-C sensor. Check the links bellow for a thorough explanation. But in a nutshell, full frame sensors are better than smaller sensors, because they render colors and values better. The field of view bit, might not mean much what we shoot, but I suppose better colors are important. Also, there are lenses made for full-frames and those made for smaller sensors. A full frame lens could work on either, but if you say put a APS lens on an full frame body, the image might have vignetting.

http://photographylife.com/nikon-dx-vs-fx

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm


White balance

White balance is one of those crucial things to know about photography, like how to turn the camera on. Below is a good explanation. However, it in the dental photography setting we’re likely to be shooting on the Flash white balance setting. However, sometimes you might need to tweak the white balance. You should look for a camera that allows you to dial in the color temperature you want, and not just offer you presets.

http://www.cambridgeincolour.com/tutorials/white-balance.htm

So basically, you’re looking for a D-SLR, a 105mm macro lens and a twin flash. But also a camera that allows you to control flash in an easy way and to control the white balance more effectively. Cameras are different. I remember reading someone say, that you should buy the cheapest body available and invest in the lens. You should definitely invest in the lens. Especially a full-frame lens. But I wouldn’t buy the cheapest body possible. Because it will create limitations sooner or later.

I hope this helped. And if you have any questions that I could actually answer, I'll be glad to help out.

 

[RileyS]

I'll refer back to this when I start to buy. You have some examples of photos?

 

[doug]

Interesting stuff. I think Jon Berry posted pages of info about digital photography for dentistry on here somewhere.

 

[Ahmadkawi]

Well, I have a ton pictures taken with my camera, that are somehow all non-dental I'm afraid. I do have pictures from work though. Taken with the clinics camera. The setup we have there is a Sony Alpha 35 D-SLR, a 50mm macro and the Sony Macro twin flash. I never paid attention to the 1:1 reproduction ratio though. And when I did, I found that do that with the 50mm lens is quite difficult. I'll see if I find any photos that would be helpful.


I tend to live by the rule of if you want honey go to a bee. So I want to buy a camera I'd go to a company that makes them. Nikon and Canon are the popular names that come in mind. And if you look online you'll camera kits made specifically for dental photography. But there are many companies, other than those too. That being said, I should say that the Sony camera we have is actually very good, and I hear that her bigger more expensive sisters are very good indeed.


I did a lot of research before I bought my camera, but I missed certain things that I have now learned, which is really the point of writing this. It's a cautionary forum post. So now you know what to look for in a camera. I suppose, that if I had waited a while, I would've bought a Nikon D600 or more optimistically a D800. Boy ,oh boy!


By the time I went to bed, I realized that I forgot to talk about two things; RAW files and Focus Motors.

Focus Motors

Lenses autofocus using an autofocus motor which is either built in the camera or the lens itself. For instance my D3200 doesn't have a motor, and for me to use autofocus – which I actually don't – I have to buy a lens that has the focus motor built in to it. In the Nikon world, those would be AF-S lenses. Bigger Nikon cameras like the D700, D600, D800 and upwards have a focus motor, so they can use AF lenses. There are lenses that are strictly manual though, and they would need manual focusing on any body.


I'm not sure of the terminology when it comes to other brands, so you'd have to the homework I'm afraid.

RAW Files

Suppose you have a D-SLR and you go into the settings for file format and you choose JPEG. What happens is that the camera doesn't shoot in JPEG. It shoots in RAW then does some processing to convert it into JPEG, which means a smaller file size with loss of detail. Check the link below for more information. But bottom line is, you should shoot in RAW, and so you should make sure that the camera you're using offers RAW.


As it turns out RAW files are not strictly universal. Each company has it's own propriety RAW format. Nikon calls it NEF for example. I forgot what Canon calls it. However, some camera companies agreed to use the DNG format which is the universal RAW format introduced by Adobe. Companies offer programs that convert their RAW into DNG, maybe not. Either way, you could download Adobe's DNG converter from their download section. It's for free, and it updates frequently its support for different camera models.


http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm


If you use something like Adobe Lightroom, you can import the pictures as DNG. I'm pretty sure you have heard about Adobe Photoshop. Lightroom is a cool RAW processor with less functions than photoshop and a cheaper price as well. You can have it to catalog and edit your pictures. It's easy to use, not to mention fun. Especially, if you're interested in photography in general, then it's kind of a must to have. If you're a Mac user, then there's Aperture, although Lightroom works on Mac as well.


If I think of anything else. I'll add it to the thread.

 

[user name]

Hey there Ahmadwawi...I just found your thread. Im changing hings a bit..I have been using a Nikon D-60, 105mm with a ring flash, but I just picked up Nikon D3200 and a R1 twin flash. (actually an R1C1, but my D-60 doesnt have a commander mode and I dont like needing to use the SU 800 commander; thats why I picked up the D3200).

Would you please chime in with your settings and add another voice to the manual/aperture question I posted here:
http://dentallabnetwork.com/forums/threads/cameras.20389/

 

[Travis]

@Ahmadkawi

 

[user name]

@Ahmadkawi

Thanks Travis. I just assumed everyone here monitors the conversations as much as I do

 

[CreativeTech]

A very interesting thread which I'll be following closely so as to improve my dental images.

Fwiw I shoot a Canon 50D, 100mm macro, & Canon Macro Twin Lite MT-24EX.

 

[user name]

Hey there Ahmadwawi...I just found your thread. Im changing hings a bit..I have been using a Nikon D-60, 105mm with a ring flash, but I just picked up Nikon D3200 and a R1 twin flash. (actually an R1C1, but my D-60 doesnt have a commander mode and I dont like needing to use the SU 800 commander; thats why I picked up the D3200).

Would you please chime in with your settings and add another voice to the manual/aperture question I posted here:
http://dentallabnetwork.com/forums/threads/cameras.20389/

Turns out I got some bad advice(not from anyone here)...the D3200 doesnt have 'commander' flash mode. grrr

Nikon rep says its got to be a d7000 or above in the current generation of bodies.

 

[2thm8kr]

Turns out I got some bad advice(not from anyone here)...the D3200 doesnt have 'commander' flash mode. grrr

Nikon rep says its got to be a d7000 or above in the current generation of bodies.

Hang them by their toes!

 

[Ahmadkawi]

Turns out I got some bad advice(not from anyone here)...the D3200 doesnt have 'commander' flash mode. grrr

Nikon rep says its got to be a d7000 or above in the current generation of bodies.

Elo there, I'm sorry I couldn't reply earlier.

Yes, the D3200 doesn't have a built in Commander Flash. That's why you need the R1C1 because of the SU-800 commander unit. But to be honest, a wireless commander unit is quite handy.
For the time being you're only using the two little flashes that make up the R1C1 kit. Once you start using more flashes, the SU-800 becomes very useful. It's true that if you have a camera body like the D700, D7100 or D7200, you can control the flashes from the camera. but it's not as easy.

I used to have a D3200, but I changed to a D7100 for several reasons. One of which was the low light / high iso performance. However, if you're always using the camera at a ISO100 and a twin flash, then the high iso performance becomes irrelevant. It's just that I use my own camera for almost everything but dental photography. Where I work we have a Sony Alpha 35 with the sony twin flash kit. it's ok.

Outside work, i'm into photography in general, here you can check out my photography on my website: www.ahmadkawi.com

As for Settings

Shutter Speed: the highest shutter speed possible that's allowed to sync with the flash. you're lens is a 105 so you should really shoot around 250 or maybe up to 320. you should be able to find in the menu the maximum flash sync speed.

Aperture: This is a bit tricky. You see, as you know that a lens wide open is a lens with a very shallow depth of field. this is awesome in general for certain reasons but none of them relate to us. at least not in the typical dental photograph. Meaning. That if you shoot two centrals with a 105 at f2.8 or f3 or even f5.6, you'll probably find the laterals out of focus. the wider the aperture, the shallower the depth of field.

Ok, cool, so does this mean I should close down my aperture to the smallest f stop? Well no. unfortunately lenses suffer from optical problems at both the widest aperture and the smallest aperture. for instance, a 50mm lens at f1.8 might give you nice bokeh and a good amount of light, but you don't have that much in focus and the image is not sharp enough sometimes. that's why lenses with big apertures are very expensive. like compare between a 50mm or 85mm at 1.8 and 1.4.

At the smallest aperture, something called light diffraction happens and also leads to loss of sharpness. you should check out some technical reviews. I have the 105mm micro nikkor. a very technical review said that the best performance is around f11. however, I end up shooting at f16 or f18. because the closer you get to an object, the wackier the depth of field becomes.

Iso: 100 of course. or the lowest possible.

Flash Settings: well, I think you could leave it on TTL, and if you feel that image is too bright or too dark, you can dial in your flash compensation. So you would understand what the problem is, it's that the camera meters the values it sees, but it doesn't know what it sees. if you're using Spot Metering and the spot is on a white tooth, the camera translates it into overexposure and tries even it out gray.

Or you can ditch the TTL and go manual. and you'll probably set to something very low like 1/128 or a bit more.

However, I do recommend you use diffusers and / or bouncers.

 

[Ahmadkawi]

I forgot to explain a bit about the images I posted.

Image 1: The PFM crown was shot in a light tent, with two flashes; a Nikon sb-700 and a Godox TN-680. the flashes were pointing away from the cast and bouncing off two sheets of white paper.

Image 2: this was lit with a studio head + softbox. the white background is the flash actually.

Image 3: was also lit with the same studio head + softbox. although I think I used another studio head + softbox to fill in some of the shadows on the right.

 

[user name]

I forgot to explain a bit about the images I posted.

Image 1: The PFM crown was shot in a light tent, with two flashes; a Nikon sb-700 and a Godox TN-680. the flashes were pointing away from the cast and bouncing off two sheets of white paper.

Image 2: this was lit with a studio head + softbox. the white background is the flash actually.

Image 3: was also lit with the same studio head + softbox. although I think I used another studio head + softbox to fill in some of the shadows on the right.

I visited your website. Very nice.

Would you please explain how and why a 'gray card' is used?

Also..when we look at teeth to take a shade, the color of lighting is so important, but what about the color of a flash? Is there any difference in the spectrum of different flashes, and what type of lighting is it comparable to?

When I shoot on either manual or aperture priority, my photos look nearly identical, but one is usually just a slight bit brighter. Do you have a preference on shooting modes, and do you always use a filter to soften the flash?

Lastly, I think it ties in to the gray card thing...how do we know when a photo we took is accurately represented on the computer screen? Is there a particular software that you like to adjust the photos, and does the gray card or some other test pattern that could be photographed get used to dial in the screen or each photo?

 

[Ahmadkawi]

I visited your website. Very nice.

Would you please explain how and why a 'gray card' is used?

Also..when we look at teeth to take a shade, the color of lighting is so important, but what about the color of a flash? Is there any difference in the spectrum of different flashes, and what type of lighting is it comparable to?

When I shoot on either manual or aperture priority, my photos look nearly identical, but one is usually just a slight bit brighter. Do you have a preference on shooting modes, and do you always use a filter to soften the flash?

Lastly, I think it ties in to the gray card thing...how do we know when a photo we took is accurately represented on the computer screen? Is there a particular software that you like to adjust the photos, and does the gray card or some other test pattern that could be photographed get used to dial in the screen or each photo?

Thank you for taking the time to look at my photographs. I appreciate it.

Ok, Grey Cards. The thing is that camera's only see shades of grey, from white to black; Values. 18% grey is the neutral grey as far as I can remember. You usually use it in situations when White Balance is tricky. for instance, you're doing a photoshoot and before you shoot your subject, you take a picture with the grey card in frame, then go about your business. Later on, in post-processing, the White Balance tool would have an eye-dropper tool that you use to click on the grey card in your first photograph to tell the software that this pixel should be 18% grey and the software adjusts the white balance accordingly.

To be honest, I don't think it matters much in dental photography, because the lighting conditions are pretty much always the same. which brings us to the other point you raised. Flash heads are set to a color temperature of course. usually it's around the recommended 5600 kelvins, but you should always go through the manual. But this is nothing to worry about really, you can always change the white balance in post-processing as long as you're shooting in RAW format. Always shoot RAW.

Color management in photography is a very, very big issue. So i'm going to include a link at the end about Photography Printing. It might sound a bit irrelevant. but trust me, the guy discusses the important stuff about color management between camera and computers. trust me it's a must watch.



I'm always shooting on Manual. Other shooting modes are useful in other circumstances. In dentistry you're probably always shooting on the same settings. once you start using Aperture priority, the camera starts changing some of the settings accordingly to achieve the exposure it thinks is correct which might be, in reality, incorrect.

I use Adobe Lightroom. You can subscribe the Adobe Photography Yearly bundle which includes Lightroom and Photoshop. Lightroom is awesome. It's pretty much the standard for cataloging your images and processing them. There are others, but that's what I use. And I think Lightroom beats everything else in cataloging, which is something you definitely need to keep track of the images.

One important thing, is how you use the photograph. I use photographs in color and in black and white.

The most important thing in shade selection, is getting the values right, because this the parameter eyes are most sensitive to. So you take a picture of the shade tab next to the tooth (always at the same level and edge to edge) and you later convert it to black and white to see about the value.

As for the color part, you shoot with a twin flash kit that has a determined color temperature. you take the image that works with a color space that's transferred to a computer and displayed on a monitor that might not be showing the same colors. it doesn't really matter. because at the end what you need is a reference. at the end you can say something like "hmm, ok it's a bit more orange than 3M2" you know what you mean?

Sorry that ran a bit too long, but I like to give thorough answers when I can.

 

[user name]

Your answers are terrific. Thank you for taking the time to teach us.

I have been given conflicting advice on shooting in RAW vs jpeg. What is the difference?

Again...Thanks.

 

[Ahmadkawi]

Your answers are terrific. Thank you for taking the time to teach us.

I have been given conflicting advice on shooting in RAW vs jpeg. What is the difference?

Again...Thanks.

Thank you. It's my pleasure. Well, it's true there's a bit of a conflict on what use, RAW or JPEG's. There is a difference of course, but it's a matter of what you're trying to do.

A camera takes a photograph. the initial image off the senor has a lot of info, dynamic range, color, shadow and highlight details. The file is big and has a lot of data. The digital camera whether it's your dslr or phone, processes the images, working on contrast, color, sharpening, etc. and then compresses the picture into the JPEG. So you have a smaller file with less details, and also less long term integrity. JPEG's are lossy files. their quality deteriorates by time. every time you open the file and change something and save it, it loses something.

RAW files are basically the digital negative off the sensor. it has all the details and it's lossless. it becomes very handy when you're post-processing.

I think the main problem with RAW and JPEG's is that RAW is bigger, but to be honest, with storage becoming big and cheap these days, it's no longer an issue. Stephen Chu says you can shoot JPEG's, Ed McLaren says shoot RAW. I say just shoot RAW with your work pictures, and shoot JPEG's for your other pictures. you know, family, friends.

The thing about RAW though is that it's unprocessed. On a camera's backscreen you only see JPEG's. camera's don't show RAW files. instead they show a JPEG version of the RAW file. when you finally see the image on your computer you'll see it as dull, with little saturation and contrast, so you have to process it. Since you're shooting with a kit with constant settings, you can create processing presets in Lightroom and apply them to photographs you took for a case. You won't be doing a lot of processing anyway. or well, it depends on what you're trying to do with the pictures. is it just for shade reference, or for something artistic and silly like the ones I posted earlier.

In camera, there are presets too, like Neutral, Standard and so on. You could shoot using one of them as long as the picture isn't more saturated than it should be. And you could export the images to JPEGS from the Nikon's View NX.

This is how I handle myself outside work. Or would handle it if i'm working on my own dental photographs. Where I work, I shoot a Sony camera, there's no Lightroom and I have to shoot on JPEG's against my will. So, naturally, I don't do anything with the pictures. It's still a point of reference. I de-saturate to see value. I sometimes lower exposure as this helps one to see texture and internal anatomy. You just got to start doing it and figure out your own system.

My workflow:
I import images from camera to computer / external storage, using Nikon's View NX.
The images are grouped into dated folders. You can easily do this in View NX. In the Transfer section, you can choose that the program transfers only new picture, and how to rename the files and the folders.
I later import the images I want to work with into Lightroom for post-processing. You could however used Nikon's Capture, the free version which works on the images in their original folders and integrates with View NX.

Lots of info, right?!! : )

I have to go now, but do keep asking questions and i'll reply as soon as I can.

 

[user name]

Im not sure what was 'dumb' about that, or if its just my line of questions, but Ill accept it. A couple more questions and Ill be dumb no more.

Histograms. Mine are all over the place...I mean, inconsistent. Sometimes much more on the left, others spiking on the right. I think the spikes on the right are due to reflections from the shiny shade tab holder. When looking at the histogram of a particular shot while Im right there with the patient, whats the tool to get more balanced information? Exposure comp?

My next question is on lenses. Im using a Sigma 105mm macro. Would there be any difference using the nikkor 105? I think its curious that my lens gets longer or shorter depending on zoom, but the Nikon Nikkor is a fixed length.

I made notes while reading, but as I re-read your stuff Im not seeing what I wrote down...color space: Adobe RGB. What was that about?

 

[Ahmadkawi]

Yeah, I'm not sure what was dumb about the question either. Moving on. Ok Histograms and lens that grow and shrink.

Histograms, are the way to check that your exposure is correct, true, but could be misleading. For instance, there are high key images and low key images. if you're shooting a model for instance in a black dress against a black background, you bet the histogram would be almost totally on the left. but that's because there's a lot of black in the image, not because it's underexposed. Remember the camera sees values but doesn't know what it really sees. Exposure Compensation is a different thing. That's what you use if you're on Aperture or Shutter priority. or basically a mode where the camera is doing the work. it might figure out the exposure incorrectly, and that's when you do exposure compensation. as in telling the camera to overexpose or underexpose by a stop or something.

As for the lenses. the 105 Micro-Nikkor uses IF, Internal Focusing. The lens elements move and rearrange inside the lens body to achieve focus. Some other prime lenses have to extend, get longer or shorter to focus. not to be confused with Zooming on Zoom lenses though.

A 105mm, or 50mm, etc, is called a Prime Lens, a fixed focal length. Focal length is basically the distance at which the image coming out of the lens forms. the focal plane. which happens to be the film negative or the digital sensor. the lens name comes from that distance. a 105mm lens is farther away from the digital senor than a 50mm lens.

Zoom lenses come in focal ranges, like 18-180, or 28-70mm, etc. which means that the lens elements rearrange to increase the distance from the sensor.

 

[Greg Lutke]

Interesting thread. Color accuracy is a big deal in dental photography and is largely misunderstood.
I have taught digital photography and Adobe Photoshop courses in dentistry for 16 years. Loved every course.
I will humbly add my experience here and hope it helps.

For color accurate dental photography, you do need a 'custom white balance'. This is captured inside the DSLR camera for jpeg files using a White Balance Card (WhiBal, XRite, or similar) - not a 18% gray card, which is for exposure management. 18% gray cards are not spectrally neutral - which is absolutely necessary.
Once a custom white balance is set in the camera - it will be applied to all future jpeg captures. The result is color accurate photography from this point forward.
The White Balance Card is Neutral - and is used to neutralize the lighting source. That source is almost always a flash in dentistry. Flashes are never neutral, but a custom White Balance makes the camera think so and the jpegs are then color accurate.
Raw files do use this Custom White Balance (captured in the camera) as a 'suggestion' in Adobe Photoshop Camera Raw or Adobe Lightroom. You do have a better option to use the Custom White Balance Tool in Photoshop Camera Raw/ Lightroom to get a more accurate result.
The result is perfectly accurate shade tabs, skin tones, and dental tissue. Capturing/Using a Custom White Balance is the best 5 minutes a dental photographer will invest.

 

[user name]

Interesting thread. Color accuracy is a big deal in dental photography and is largely misunderstood.
I have taught digital photography and Adobe Photoshop courses in dentistry for 16 years. Loved every course.
I will humbly add my experience here and hope it helps.

For color accurate dental photography, you do need a 'custom white balance'. This is captured inside the DSLR camera for jpeg files using a White Balance Card (WhiBal, XRite, or similar) - not a 18% gray card, which is for exposure management. 18% gray cards are not spectrally neutral - which is absolutely necessary.
Once a custom white balance is set in the camera - it will be applied to all future jpeg captures. The result is color accurate photography from this point forward.
The White Balance Card is Neutral - and is used to neutralize the lighting source. That source is almost always a flash in dentistry. Flashes are never neutral, but a custom White Balance makes the camera think so and the jpegs are then color accurate.
Raw files do use this Custom White Balance (captured in the camera) as a 'suggestion' in Adobe Photoshop Camera Raw or Adobe Lightroom. You do have a better option to use the Custom White Balance Tool in Photoshop Camera Raw/ Lightroom to get a more accurate result.
The result is perfectly accurate shade tabs, skin tones, and dental tissue. Capturing/Using a Custom White Balance is the best 5 minutes a dental photographer will invest.

One more time, and walk us through this please. You also mention shooting in jpeg...not raw?