With my D750 set to sRGB, flat picture style, and auto WB, I took exposures of all three colors with the ‘middle grey’ exposure value indicated by the camera meter when metering the green layer (this was 1/15 f/5.6 ISO 100 for my monitor’s brightness). I created the three layers for R, G and B respectively in PS in the sRGB color space. I believe I followed your procedure as best as I could interpret, however I’m fairly confident I’m not getting the correct coefficients as the review images of subsequent exposures do not have the green cast I’m used to on my Canon 7D when using my UniWB exposure. I’m trying to create the custom WB image for UniWB on a Nikon D750. Next: The math behind the one-step method You can check the EXIF data to make sure. Look at the average values for R, G, and B.Įnter those values into the result column of the spreadsheet and read the coefficients. White balance to the test image, then photograph it and bring the raw file into Rawdigger. Enter the trial monitor values into that dialog.įill the white balance layer of your test image with the foreground color: In Photoshop, click on the foreground color square to open up the color picker dialog. In this case, it’s Adobe (1998) RGB, which has a gamma of 2.2 except near 0. I entered 4000:Įnter the gamma of the color space you’re using in the image editing program. It’s not important what this number is, as long as it’s not so small that there’s a lot of camera noise to deal with, or so large that the monitor can’t get bright enough to reach it. In the entry cell at the Desired camera values column, put a number that is less than the smallest number in the monitor measurements matrix diagonal. Ignore the G2 channel:Įnter the blue channel information into the first column of the monitor measurements field in the spreadsheet: Ignore the G2 channel:Įnter the green channel information into the first column of the monitor measurements field in the spreadsheet:īring up the blue image in Rawdigger, and look at the average for the R, G, and B channels. Ignore the G2 channel:Įnter the red channel information into the first column of the monitor measurements field in the spreadsheet:īring up the green image in Rawdigger, and look at the average for the R, G, and B channels. Don’t worry about the error messages they’ll go away when you fill in all the input cells:īring up the red image in Rawdigger, and look at the average for the R, G, and B channels. Here’s what the spreadsheet looks like when you open it:įirst, clear all the input cells so you don’t get confused about what you’ve entered and what you haven’t. Photograph each of the three layers with an exposure that’s about what your built-in meter recommends for the green layer and bring the files into your computer. Use Edit>Fill… to fill the red layer with the foreground color:ĭo the same with the green and blue layers. When the colors are all filled in, the layers will look like this:Ĭlick on the foreground color and enter the values for full red as follows: Then make a fourth layer for the white balance target color. To make the red, green, and blue images in Photoshop, create an image about the shape of your format. Bring that picture into Rawdigger and look at the EXIF WB coefficients and the raw values to see how well you did.Read the UniWB target RGB values from the output cells, and fill the test target with that color in Photoshop.
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