My first rule in dental photography: SHOOT IN RAW. The camera’s RAW format is a digital image file format that contains all of the image data as captured by our camera’s sensor, that´s the reason why they are known as the “Digital Negative.”
These kind of files are the only photographic files that have a legal value in case of having issues with our patients and what we must put forward as evidence.
Due to the rivalry between the brands of cameras, there is no universal file extension. Thus, Nikon will have a .NEF extension, Canon a .CRW or .CR2, Sony .ARW, etc. This has meant that the largest developer of image editing software, in an attempt to unify criteria, has created the .DNG extension.
This is an open- source extension, so it has a bit more compression than the original ones, without losses as well and allows any editing software to read the files.
These files have a greater amount of information than the JPG files, and therefore they have a greater capacity for recovering details of the shadows and lights, saturated tones and so on.
Besides it’s possible to select later a suitable white balance in an edition software.
As its name indicates, these files are “crude.” So they usually have muted tones, lack of sharpness and so on, It is mandatory to process them.
We’ve all seen in our camera’s menu an option that indicates WB. But what the hell is exactly the white balance?
The white balance refers to a feature of light: temperature
As we all know, light travels in the form of waves, and these can be larger (longer wavelengths) and give off reddish tones or shorter ones (shorter wavelength) which give off bluish tones.
When we put a white paper underneath a light source (any), our brain makes the necessary adjustments for us to perceive it as white, although the color that reflects the light keeps its dominance and this appears on the paper.
Well, this same process, which is automatically and constantly made by our brain, our camera is not capable of doing it alone, and we will have to be the one to indicate it whether with its settings or the adjustments of processing in RAW.
Our camera, or better to say, the sensor of our camera is set up in a way that a correct exposure of a scene is the one in which, when performing the light measurement of the scene, no matter what it´s, the percentage of light reflected by the objects will be 18%, that is, the value of “middle gray”.
Thus, to adjust precisely our shots, it is necessary to make at least one shot of a middle gray card at 18%, not at 50% as you´re thinking, but I will explain it in another post.
There are models and brands of gray cards galore in the market, but I recommend Whibal (you can purchase it here).
This model has shown that it has an optimal luminance value to use for the color taking, but like everything in this life, there exist cheaper although less precise Chinese copies which are also useful for our purpose (you can purchase them on aliexpress).
The main functions of the gray card would be:
· Choosing the right exposure
· Adjusting color balance
· Setting the lighting up in the correct way.
But don’t worry if you have not been able to get one because owing to the fact that the flash is used in a ninety percent of our shots, light is going to be much the same in all the shots, so the only thing we have to do is adjusting the color temperature at 5500 ° K which is, more or less, the standard color temperature of most flashes.
In the case of Nikon sbr200 flashes (the twin) when they shoot at ¼ of their power, they give a temperature of 5700ºK.
It is also remarkable that white balance may be used only to adjust color dominances and values of exposure but not to correct the image colors.
HOW TO USE THE GRAY CARD
In the first place, what we have to do is taking a photo of the card beside the object we’re going to snap and under the same light conditions.Next, we will go to any editing program to edit the image, and there we’ll give correct values to the color temperature.
- In Lightroom, we pick out the picture which has the gray card.
- Enter the develop module by chosen it from the right-hand upper corner.
- On the right panel, just below the histogram in the basic tab, we see a dropper, click on it, place it in the middle of the card and click.
Now we’ve got our white balance for this photo session but only for one snap. To apply this to the rest of images, we’ll follow some advice.
- On the capture with the corrected white balance, in the develop module, choose the Copy option on the left-hand panel.
- Then, a dialog box will appear, and we only have to choose white balance and process version (leave the rest without choosing) and click on Copy.
- Next, we pick out all the snaps of the session (press Control and click on the photos).
- Finally, we click on Paste on the left-hand panel.
So, we now have all the snaps with the white balance corrected.
One tip to use it on the color shade taking photographic protocol is taking one of these cards, cut it into pieces of 1 centimeter per 1 centimeter and put it on a stick.We put the shade guide tooth beside the stick with a piece of the gray card we’ve already cut and the patient’s tooth, note that the color guide, the patient’s tooth and the piece of the gray card must be on the same level.
Although the white balance may help us in a ninety percent of the cases, there might be some color alterations in the snap.
Our camera is not flawless, and although they are usually calibrated, there are color variations concerning the one we actually see. In these cases, we should use the color card rather than the gray card. Besides, these cards have a gray card attached.
A color card is just a colorful card which has got fixed values assigned to the different hues to create a color correction profile with the aid of specific software.
WORKFLOW WITH A COLOR CARD
As with the gray card, the first thing we need is a snap of a card of colors.
- If we use it for an extra oral photo, we have to shoot a snap of the card beside the person who appears on the photo from a frontal perspective and as perpendicular as possible using the same light that we will use during the session, that is, with all the flashes well calibrated, etc..
- If we use it for an intraoral photo, we have to shoot a photo of the card of colors using a flash. This photo, as it happens with the rest, has to be shot in RAW format.
- Convert this image to a DNG format, which is the universal RAW format created by Adobe. We can get this utilizing a converter, Lightroom or with a RAW camera. I leave here a link where it’s explained how to do it in Spanish or with Lightroom.
- Open the Passport Color Checker software and drag the image here.
- Place the green points of the squares in a way that all squares appear over the colors of the card.
- Click on create profile and save in C:/Users/XXX-lap/Appdata/Roaming/Adobe/CameraRaw/CameraProfiles.I hardly recommend putting specific names where appear the model of camera, lens used and light conditions, for example, Nikon D7100_Sigma100_TwinFlash_clinic
- Once the profile is created, we open LR in the develop module. On the right-hand menu, in the camera calibration tab we may see the new profiles If you click on the newly-created profile, we will apply all the calibration values and watch how our image automatically changes.
PROCESS YOUR RAW ARCHIVES
As we’ve already said, to work with the images we’ve got to shoot in RAW. A RAW file is a file that has not been processed.
Formerly, when you shot with reel, we’d take the reel to the shop and later received the photos on paper… But what happened in between?
Well, there was a specialist who made the necessary adjustments to brightness, saturation, and contrast to our negatives. Nowadays, we don’t have to take our photos to any place. Therefore, we have to make these basic adjustments by ourselves.
Well, there was a specialist who made the necessary adjustments to brightness, saturation, and contrast to our negatives.
Nowadays, we don’t have to take our photos to any place. Therefore, we have to make these basic adjustments by ourselves.
I´m going to show you my workflow, and how I process my photos, this is something personal, and it is pretty likely that everyone of us has his own style.
BASIC PROCESSING IN LIGHTROOM.
- The first thing we’re going to do is picking out the snap we want to process and enter the develop module by clicking on the tab which is on the upper-right hand.
- As we’ve already said, we charge the color profile which was created for the camera underdetermined light conditions, and in the camera calibration tab we open the drop-down window and choose our desired profile. In the image, you’ll see a lot of profiles that I have downloaded or created for my photos.
- Straighten the image and cut if necessary with the cutting button.
To use this tool, is quite simple, first of all, we have a padlock at the right hand, when you click on it, it can be open, giving free movement for cropping, or close, that option maintains the selected format for cropping.
You can select a fixed format by clicking on “original” and select if you want a square cutout or 16×9, etc… Also by clicking on the squad nearby Aspect, you can do it by hand.
With the Angle option, you can straighten your image with the slider or click on the rule and select in the snap the incisal borders that have to be horizontal.
- Low the highlights to -90 or -95.
- Increase shadows to 90 or 95.
- Adjust the whites and blacks. While pressing the Alt key, we move the bars to the right ( whites ) or the left ( blacks ) until we see marks which indicate an excess of blacks or whites.
- Add a little bit of clarity so as to see more clearly the edges of our photo and bring out more details of it.
Here is an example:
Dental photography is a tool that we all have within reach; it is very powerful to see a magnification of our works, letting us see our mistakes and improve all of our treatments, that´s the reason why I think it must be mandatory in our daily practice as a dentist.
Also, as you have seen, it is really simple to give a professional look to our pictures with this few tricks.