Atlanta portrait and wedding photographers Craig & Cathy Willis

770-439-6065

Color by the Numbers / Kodak Color Chart


Even the best calibrated monitor can be off at times, but knowing the value of the color by the numbers you can adjust an image and be sure it is adjusted correctly.


Making Accurate Color Adjustments to Your Digital Files


First lets take a second to look at the Kodak color chart.


The point of reference to balance to white is just under the A in the grayscale top part.

The point of reference to balance the black is under the B in the grayscale top part of the chart below.

The chart can help you in a couple of ways, first of all you can adjust color by the numbers by knowing the value of the color you wish to have.

Pure white for example is Red 255 / is Green 255 / is Blue 255 while pure black is is Red 0 / is Green 0 / is Blue 0

Now lets explore the practical side of adjusting a photo using the principals of adjusting your color by the numbers.

The photos use in this example are from a wedding, and with most weddings you are going to find two colors almost every single wedding.

White, and Black, which are the two best for doing any color adjustments by the numbers.

I have two programs that I like to use, Photoshop CS2, and Nikon Capture.

I personally like Nikon Capture to work my RAW NEF file format images, because the workflow is much easier, and allows me a bit more control, and has more tools.

However, Photoshop is the more popular photo editing software used by professional photographers, and will allow other camera brands raw files to be worked with, so I will first do my example with Photoshop CS2 using Adobe Camera Raw or ACR.


Using Accurate Color Adjustments with Adobe Photoshop CS2


Click image for a fullsized screenshot in a new window.

• First you want to pick a spot that you want to be WHITE when the image is properly adjusted.

• Second pick your black spot.

Using the color sample tool near the top left of the image you can click on the area you wish to see what the color value actually is according to the camera settings you picked when you captured the image.

The tool next to it, can be used to auto color correct, and that is fine for a lot of people, I just like better control then auto adjustments give you.

• First adjust for the white you picked, if your color balance is off, it will show up more in white then with black.

I like my white areas to not be at 255,255,255 or absolute white, because that tends to lose detail and gives a "blown out" look.

I will normally make my adjustments to get right at 240 on each value.

Before making any adjustments, that color sample point may not be anywhere near what you are hoping it would be, so you have three sliders that you can adjust to get all three numbers as close to the same as possible, and to get the value of them near the level that you are looking for.

For example, using the color temperature slider you move left or right, and look at the values of the Red Green and Blue numbers, and get as close to even for all three as possible, at this point there might be 3 to 5 points off on one of the three.

Then using the tint slider, adjust left or right, again to get the value of all three numbers equal, or at least as close as possible.

In this example I adjusted until there was no more then 1 point difference between the three, and ended up with, Red 240, Green 239 and Blue 240.

However until I adjusted the exposure slider, the three numbers were in the 220 to 230 range, using the exposure slider, I brought the value of the three up to as close to 240 as possible, because at 240 you will get white in print, and yet still have detail in the dress.


• Now to get the blacks to be black, or at least close as possible.

This step is different to achieve with ACR compared to Nikon Capture, but to get white is almost the same by the way.

With ACR, you simply adjust the shadows slider to the right until you get your highest value to be 10 or less, if your at that value you will get good blacks in your prints.


Using Nikon Capture


Click image for a fullsized screenshot in a new window.

As mentioned before, to work RAW NEF files, I prefer the Nikon Capture program, it saves storage space overall, and the workflow is much more simple, and takes less time overall to process 1,000 images from a wedding then using ACR with CS2, but both will do a great job, as far as quality of the final image, both are about equal if you know the programs well and know how to get the most from the program.

Here is an image from the same wedding, but showing the tools with Nikon Capture to make the same adjustments.

• First you want to pick a spot that you want to be WHITE when the image is properly adjusted.

• Second pick your black spot.

Using the color sample tool in the "information" tool of NC, you can click on the area you wish to see what the color value actually is according to the camera settings you picked when you captured the image.

First adjust for the white you picked, if your color balance is off, it will show up more in white then with black.

I like my white areas to not be at 255,255,255 or absolute white, because that tends to lose detail and gives a "blown out" look.

I will normally make my adjustments to get right at 240 on each value.

In Nikon Capture you can use set gray point, or use select color temperature, to do this type of color by the numbers that I am talking about it's best to not use the select gray point, but using the select gray point tool does work well, and I use it all the time.

In this example I picked >daylight >cloudy and then adjusted the slider until I got the value of the R B and G to be equal within 1 or 2 points.

If your off too much on that value you would want to go to the color balance tool and fine tune the color as you need to there.

As you make these adjustments, the reference points do show the change in value in both Nikon Capture and with ACR.

Now just like with ACR, you adjust the exposure, with Nikon Capture that would be >advanced raw toolbox, and adjust the slider until you get the value you are looking for, in this case close to 240 is normally my goal.

Again until I adjusted the exposure slider, the three numbers were in the 220 to 230 range, using the exposure slider, I brought the value of the three up to as close to 240 as possible, because at 240 you will get white in print, and yet still have detail in the dress.


• Now to get the blacks to be black, or at least close as possible.

This step is different to achieve with Nikon Capture compared to ACR, but to get white is almost the same by the way.

With Nikon Capture you move the slider at the bottom of the histogram found in both the LCH tool and the Curves tool, move that left side point until you get to the peak of the left edge of the histogram and that will snap those blacks into place after having adjusted the exposure up.

If you are shooting in JPEG file format, you can do all of the things mentioned, just you need to use tools that are not found if you were to have shot your image in RAW.

For example the color balance tool with NC, you can adjust the Red Green or Blue, or you can use curves to make your adjustments, with curves you can adjust each color channel as needed. But Photoshop Ctrl+B is the shortcut for the color balance tool, and you use it to make the changes needed to get your sample point adjusted.

Never pick as your white spot an area that was blown out or overexposed, it will make it much more difficult to balance.

There are occasions where I have tweaked the balance more towards the black sample point to get the look I was looking for.

It is far better to shoot to not blow out highlights with digital capture then to over expose, try to come as close as possible, the closer you are the better your image will look overall.

If your images are adjusted by the number you can and should expect great printing from your color lab. Also your color calibration of your monitor is something you should consider doing, it's good to be viewing your color correctly, if your adjustments are by the number, they will be right however even if your monitor is off.

I hope that helps.

Craig




If you wish to adjust some other color by the numbers, you can do that also.

Here is an example where Shirley a member of my photography group Professional Photo Talk, made adjustments to one of her sunset photos to have a bluer sky.

The original above of Shirley's image is nice, but below is what she got after adjusting the image for the sky.

In showing this off for Shirley, I decided to crop it, and give it a title.




Back to:
Pages for Photographers