Learn how to set the white point to match a target in this Adobe Photoshop CS2 Advanced training video.
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Now at this point, let's say, we are going to press with this thing. We are going to print it in a magazine, for example. So we are going to go to our commercial printer with it. Why then, we are going to ultimately need to convert this image to a CMYK image? We might actually convert the image to CMYK ourselves or we might submit an RGB image to our printer and let the printer do the work for us, but in any case, we are going to want to know approximately what those CMYK values are going to be, to preview the CMYK values that are associated with this number 2 sample.
Notice this little eyedropper has a little tiny right pointing arrowhead next to it. That tells you that there is a popup menu potentially there. So click on the eyedropper and choose CMYK Color. Instead of RGB Color, choose CMYK Color and you will get the CMYK values. So it's going from the color was originally inside the teeth 65, 64, 75, 79, reading down the CMYK values and it will now switch to 75, 68, 67, 90.
Now you may very well wonder, well, where are those values? Why aren't they a 100% all the way down the line? Why isn't a 100% cyan, a 100% magenta, yellow and black? Well, the reason is because then your total ink coverage would add up to 400% as those four 100% values would add up to a 400% total. That means your ink is remaining wet on the page, the paper is not absorbing the ink. When it gets that much ink, it can't absorb at all and so the ink starts to run. So it's okay when the cyan is laid down, it's okay when the magenta is laid down, it's starting to run out of room when the yellow is laid down. Then once the black hits the page, it just runs all over the place. It smears, becomes a huge mess and you get just horrible, horrible results from your commercial printer.
Photoshop knows about this, of course, so it goes ahead, by default, and maintains 300% as the total ink coverage. So if you add 75, 68, 67, and 90 together, you will find that those numbers do not quite add up to 300% or 300% will be the maximum that they add up to, thereby ensuring that the paper can absorb the ink. So it's a wonderful thing, Photoshop does that automatically for you. You can adjust those values if you want to, but we are fine with those.
I am now going to lighten, theoretically anyway, at least I am going to set the colors of the highlight right here, which is target number 1. I am going to do that with the white eyedropper. So I am going to get my White Eyedropper Tool, I am going to move the cursor so that I cancel out the target, like so. So one cancels out the other and I am going to click.
Notice what happens with target number 1 now, it goes from 243, 243, 243 for R, G and B to 255 for all three of them, in other words, white. You want to analyze the CMYK values? Of course, you do. So click on the eyedropper and choose CMYK Color and it goes from being a 3, 2, 2, 0 to 0, 0, 0, 0. Now we run into a potential problem.
Now obviously, we are printing to white paper, of course. We're not going to print this to colored piece of paper because that would ruin the image because we get all kinds of interaction between, for example, this green and the color of the paper. We wouldn't get these nice, rich greens. We would get some sort of muddy color. So we are going to print to white paper.
So in absence of ink, we are not going to have any ink at this location. It's going to be 0, 0, 0, 0, so no ink. So of course, we are going to be left with the color of paper which is as white as that paper gets. Problem is, most presses can't retain a 1% dot. So if you had 1% for cyan, magenta, yellow or black, it wouldn't be able to actually completely maintain that dot. It would drop out to white. A 2% dot might drop out to white as well and a 3% dot might drop out to white and so on. Meaning that this whole area right here is potentially going to turn into a hot spot, it's going to go absolutely white, which means even though it looks good on screen, when you output this image you are going to get dots getting lighter and lighter and lighter and all of a sudden there they cut off and you are going to get a little tiny bit of banding and it's going to look bad. It's potentially depending on your image, it can ruin an image. So what do you do?
Well, you consult with your commercial printer and you ask them what is the lightest dot that they can retain? What is the actual color of white on the specific press that you are going to? They will tell you the answer hopefully with any luck and then you will go to your white eyedropper, double-click on it, brings up the Color Picker dialog box. Let's say, they tell you the definition of white for our press is 6 for cyan, 5 for magenta and 6 for yellow and then 0 for black, because we don't want to muddy up the white. We want to leave it a nice, crisp, neutral white. So let's just add cyan, magenta, and yellow ink in order to do that and then click OK.
Now check this out. I go over here to number 1, CMYK, 3, 2, 2, 0 before the change, still 0, 0, 0, 0 after the change. In other words, Photoshop does not update this value dynamically and I hate that about this tool. It's a big pain in the neck, in my opinion, but by virtue of the fact that I identified, very carefully I identified where that lightest color is, I still have my white eyedropper selected. So I will just go ahead and once again click at that exact point, so the cursor cancels out the target. Click and notice what happens, 3, 2, 2, 0 changes to 6, 5, 6, 0, just like I want it to be.
So we have now done a super-duper job of targeting the lightest colors inside the image and the darkest colors in the image. I have made sure that even though these highlights are not going to darken up, that's okay, because really when they go to the press, they are going to lighten up naturally because those halftone dots are going to get a little bit lost as they get smaller and smaller and smaller, but we are going to have a nice transition, an even transition of halftone dots right here. We are never going to clip any color, so it's going to be masterful, this image is going to print beautifully.