Posted by Mark Pelton on July 26, 2012 at 10:06 PM
Can anyone tell me how to print something absolutely white in PS6. To elaborate, I have a scanned (flatbed) image that has paper white in part of the image. I cannot get the "paper white" in the image to come out paper white. Can I make some adjustment in PS to get this "paper white" closer to actual paper white?
Posted by David Bostedo on July 26, 2012 at 11:17 PM
Mark - A white image printed on an inkjet printer should always be the same color as the paper - there's no way to get it any whiter. So if your paper is off-white, cream, tan, ecru, etc. that's the color you'll get in the white parts of the image.
If that's not the issue, Ii it possible that your printer has a gloss optimizer or other treatment it may give to white parts? Or is it possible that the white parts are slightly toned, and you have a profile issue?
Posted by Dan Borzynski on July 26, 2012 at 11:43 PM
On inkjets, whites are defined by the absence of ink. This means that a pure white in the Photoshop file is going to be limited by the tone of the medium you are printing on.
The other question that occurred to me is about the source file you are trying to print. Is the white in the scan a true white or does that part of the image need to be color corrected? A couple of ways of moving the whites in the source file would be autocontrast (quick, dirty and possibly ugly), levels (moving the rightmost slider to the left a bit to bring the whits to (255,255, 255), curves, curves white dropper sampling on the paper (maybe only slightly better than autocontrast), or some cast correction techniques to remove a color cast.
Just looking for clarification if your question is a printing question or a Photoshop question.
Thanks, guys. Dan, to clarify, I think its a photoshop question. I need to move the white in the file to a cleaner white (in essence I guess this would be the same as removing a color cast from the file?).
If the paper is pure white it should render as 255/255/255 in the scanned file or at least three equal RGB values ( I.E. 252/252/252), the difference being exposure rather than variation of hue. Your scanner software should have allowance for adjusting the color balance of the output along with brightness, contrast, etc.
Mark - What you need depends on what tones are present in the white part of the image. It's either removing a cast or possibly a white balance adjustment, or could just be setting the white point.
A cast (or incorrect white balance) would show up as color in the white part of the image. An incorrect white point would just make the whites look grey, and might make the image look a bit dark overall.
As far as correcting it, if it's just a white point adjustment, using levels and the white point eye-dropper works well, or you can up the brightness if that's better, or use curves.
If you're trying to correct a cast/white balance, I have two favorite methods, though there are lots more. The first way is to simply open the image (whether TIFF, JPG, PSD, or raw) in ACR, and use the white balance tool. The other way is in Photoshop :
-- Copy your image to a new layer on top, and do a Filter->Blur->Average
-- Make a levels adjustment layer on top, and use the grey eye dropper on the average blur layer
-- Turn off/delete the average blur layer, and adjust the opacity of the levels layer to taste
OK thanks guys, you helped me figure this out. The print was actually a scanned pin and ink drawing, and since I wasn't setting the white point in ACR, I just wasn't thinking white point. But that was all it took; I set the white point with levels and now everything is fine. Thanks again.
"-- Copy your image to a new layer on top, and do a Filter->Blur->Average
-- Make a levels adjustment layer on top, and use the grey eye dropper on the average blur layer
-- Turn off/delete the average blur layer, and adjust the opacity of the levels layer to taste
"
I use this technique (but with a curves layer instead of levels) quite a bit, and find that it works very well most of the time. Where you can run into trouble is if the color cast is very heavy. For example, let's say that the blur>average layer looks very yellow. After clicking the grey eye dropper in the the blur layer it will turn grey. Now, when you turn off the Blur layer, your image will now have a decidedly blue color cast: the grey point algorithm has over-compensated for the yellow cast by adding blue.
At this point you can either adjust the blue channel to remove some of the blue, i.e. add some yellow, or use another method to set the grey point or color balance.
As David mentioned, a key element that must not be overlooked is using the 'opacity' adjustment of the Levels layer that was constructed for removing the color cast in an image. By varying the opacity from 100% to 0% you have a large degree of control over how the levels layer will affect the color cast of the image. So, while in some cases other methods might be called for (like adding in the complimentary color), I have found that for the most part simple tweaking of the opacity slider (for the levels layer) gets the color cast to exactly where I want it.
I guess I missed the part about tweaking the opacity. I'll certainly give that a try. Thanks for that.
Added...
After giving this more thought, I believe that changing the opacity of the levels or curves layer won't correct an individual channel, if there is a need to do so.
Discussion
9 repliesIf that's not the issue, Ii it possible that your printer has a gloss optimizer or other treatment it may give to white parts? Or is it possible that the white parts are slightly toned, and you have a profile issue?
The other question that occurred to me is about the source file you are trying to print. Is the white in the scan a true white or does that part of the image need to be color corrected? A couple of ways of moving the whites in the source file would be autocontrast (quick, dirty and possibly ugly), levels (moving the rightmost slider to the left a bit to bring the whits to (255,255, 255), curves, curves white dropper sampling on the paper (maybe only slightly better than autocontrast), or some cast correction techniques to remove a color cast.
Just looking for clarification if your question is a printing question or a Photoshop question.
A cast (or incorrect white balance) would show up as color in the white part of the image. An incorrect white point would just make the whites look grey, and might make the image look a bit dark overall.
As far as correcting it, if it's just a white point adjustment, using levels and the white point eye-dropper works well, or you can up the brightness if that's better, or use curves.
If you're trying to correct a cast/white balance, I have two favorite methods, though there are lots more. The first way is to simply open the image (whether TIFF, JPG, PSD, or raw) in ACR, and use the white balance tool. The other way is in Photoshop :
-- Copy your image to a new layer on top, and do a Filter->Blur->Average
-- Make a levels adjustment layer on top, and use the grey eye dropper on the average blur layer
-- Turn off/delete the average blur layer, and adjust the opacity of the levels layer to taste
You might have your own favorites too I'm sure.
I use this technique (but with a curves layer instead of levels) quite a bit, and find that it works very well most of the time. Where you can run into trouble is if the color cast is very heavy. For example, let's say that the blur>average layer looks very yellow. After clicking the grey eye dropper in the the blur layer it will turn grey. Now, when you turn off the Blur layer, your image will now have a decidedly blue color cast: the grey point algorithm has over-compensated for the yellow cast by adding blue.
At this point you can either adjust the blue channel to remove some of the blue, i.e. add some yellow, or use another method to set the grey point or color balance.
--P
As David mentioned, a key element that must not be overlooked is using the 'opacity' adjustment of the Levels layer that was constructed for removing the color cast in an image. By varying the opacity from 100% to 0% you have a large degree of control over how the levels layer will affect the color cast of the image. So, while in some cases other methods might be called for (like adding in the complimentary color), I have found that for the most part simple tweaking of the opacity slider (for the levels layer) gets the color cast to exactly where I want it.
I guess I missed the part about tweaking the opacity. I'll certainly give that a try. Thanks for that.
Added...
After giving this more thought, I believe that changing the opacity of the levels or curves layer won't correct an individual channel, if there is a need to do so.
--P