Does this photo appear cool (color temp) to anyone?

[eric-holmes]

Yes, cs5. When I adjust WB in ACR (using the eyedropper), it makes the overall image entirely too orange. I would select something I know to be white, like her eye or a piece of her dress.

 

[clanthar]

I use Photoshop.

I took your original and began by converting it to Lab mode. I then used Levels to adjust it. In Levels I accessed the "b" channel (yellow/blue) and pulled the midpoint slider right to a value around 1.22. I made a slight change to the "a" channel (.98) and then back in the Lightness channel I adjusted the tone response: I pulled the highlight slider to the right (230) and the midpoint slider to the left (.94). Convert back to RGB. I used Channel mixer to convert to B&W.

Joe

 

[GooniesNeverSayDie11]

Follow these steps in cs5 with the image as the background...

Open new layer, fill with 50% gray....change blend mode to difference.

Open threshold layer above move slider all the way left...slowly slide to the right until you see white dots start to appear ( or is it black dots? Lol I am mixed up..the opposite color from which far left gives you. ) you will want to zoom in where they first appear and then back off a bit on the slider til just the first few pixels change color.

Use the second eye dropper tool in the tools menu ( multi point) choose 4 of the points to mark. Turn off threshold and NEW Gray Layer, open levels adjustment, use gray eye dropper to click one of the 4 pixels. Toggle layer on/off to see change. Sometimes its subtle. Sometimes you need to reset levels and try one of the other 4 points.

 

[GooniesNeverSayDie11]

Note: I originally said 50% black but meant gray...I edited the post

 

[clanthar]

Goonie, no offense intended here, but that method is seriously flawed. I've encountered it before in far too many places and it's unfortunate that it keeps spreading around. That's one of the problems with the Internet....

Photoshop's gray point eyedropper can be useful if you have what should be a middle gray tone in a photo and there's a color cast in the photo. Use the gray point eyedropper and click on that middle gray tone and Photoshop will set it to neutral and WB the rest of the photo around it. The key to successful use of the eyedropper is to have what should have been be a middle gray in the first place and be able to identify it. If you're able to do that then you should be able to correct the photo manually. The more you practice correcting the photo manually the better you get and eventually you will always be able to to a better job than any software algorithm assisted method.

Your method attempts to find a middle gray and indeed if will work if the photo contains a middle gray. (But that's not what you should be looking for!) To use this method correctly, when you have the Threshold layer active and have pulled the slider all the way to the left, anything that still shows will be middle gray. Using the eyedropper on something that already is middle gray of course won't alter the photo. With the slider pulled all the way to the left, if nothing shows then the photo has no middle gray. As you pull the slider to the right you're finding tones that are close to middle gray. It's just as likely they are already the color they should be and so this method at that point is worthless.

What you want to find is a tone in the photo that should have been middle gray but isn't because the photo has already been screwed up by software.

Joe

 

[GooniesNeverSayDie11]

To each his own, it will remove a color cast no matter how you slice it. You are correct, it is looking for a midtone of the image, not specifically gray. It also works whether your monitor is calibrated, or the colorcast is hard for you to notice minor changes to do it manually. Its a good starting point to train your eyes to see the differences once the adjustment has been made. No offense taken.

 

[davisphotos]

A properly converted black and white should not have any color balance issues, since it won't have any color.
And I agree with clanthar here-especially with photos of people, you should be able to color balance for pleasing skin tones manually-with a calibrated screen and trained eye, it's a pretty quick process, often quicker than trying to get Photoshop's guestimates to look right.

 

[GooniesNeverSayDie11]

Actually, I think my method REMOVES the guessing and is pretty straight forward. Personally I use curves in LAB mode to adjust color typically, but I think until you learn to see the colorcast, you cant manually adjust it ( and I dont mean blatantly excessive wb issues ) Many people fail to even notice it until someone points it out, or until they see a corrected version ( even if it is only a ballpark correction given some images tones and all that.)

Gotta learn to crawl before you can walk

 

[clanthar]

To each his own, it will remove a color cast no matter how you slice it. You are correct, it is looking for a midtone of the image, not specifically gray. It also works whether your monitor is calibrated, or the colorcast is hard for you to notice minor changes to do it manually. Its a good starting point to train your eyes to see the differences once the adjustment has been made. No offense taken.

No, this method will not remove a color cast. It does in fact look specifically for gray (tone and color) and if it finds it then clicking on gray with the gray eyedropper gets you nowhere and removes nothing. As you pull the Threshold slider back from the far left it includes tones (and colors) successively further from middle gray. There is no reason to expect that those tones represent a color cast; they're just as likely to be the color they should be. This method does not uncover a color cast -- you may be lucky and you may not.

Using this method as a way to WB or color correct a photo is a mistake.

Joe

 

[GooniesNeverSayDie11]

To each his own, it will remove a color cast no matter how you slice it. You are correct, it is looking for a midtone of the image, not specifically gray. It also works whether your monitor is calibrated, or the colorcast is hard for you to notice minor changes to do it manually. Its a good starting point to train your eyes to see the differences once the adjustment has been made. No offense taken.

No, this method will not remove a color cast. It does in fact look specifically for gray (tone and color) and if it finds it then clicking on gray with the gray eyedropper gets you nowhere and removes nothing. As you pull the Threshold slider back from the far left it includes tones (and colors) successively further from middle gray. There is no reason to expect that those tones represent a color cast; they're just as likely to be the color they should be. This method does not uncover a color cast -- you may be lucky and you may not.

Using this method as a way to WB or color correct a photo is a mistake.



Joe

Dude, I have used this countless times on the fly to remove colorcast and it does work. There may be times that it doesnt seem to get it just right, but then again the same can be said for doing it manually. The OP can try my method for himself and see if it holds true, if not, dont use it. Dont sit there and say that my method is "wrong" just because it is not your method.

 

[GooniesNeverSayDie11]

Also, color correcting involves setting of the black and white points as well. My technique is strictly for the colorcast.

 

[GooniesNeverSayDie11]

How To: Remove Color Cast With Photoshop | Photography - PopPhoto.com Offers Camera Reviews and Exclusive Photo Tips

Here ya go. While you are correct in saying this will not always work, it is a nice methodical way that doesnt require as much "interpretation" or guess work from you. Disclaimer: this does not work all of the time, but has been useful for me atleast 95% of the time.

 

[clanthar]

To each his own, it will remove a color cast no matter how you slice it. You are correct, it is looking for a midtone of the image, not specifically gray. It also works whether your monitor is calibrated, or the colorcast is hard for you to notice minor changes to do it manually. Its a good starting point to train your eyes to see the differences once the adjustment has been made. No offense taken.

No, this method will not remove a color cast. It does in fact look specifically for gray (tone and color) and if it finds it then clicking on gray with the gray eyedropper gets you nowhere and removes nothing. As you pull the Threshold slider back from the far left it includes tones (and colors) successively further from middle gray. There is no reason to expect that those tones represent a color cast; they're just as likely to be the color they should be. This method does not uncover a color cast -- you may be lucky and you may not.

Using this method as a way to WB or color correct a photo is a mistake.



Joe

Dude, I have used this countless times on the fly to remove colorcast and it does work. There may be times that it doesnt seem to get it just right, but then again the same can be said for doing it manually. The OP can try my method for himself and see if it holds true, if not, dont use it. Dont sit there and say that my method is "wrong" just because it is not your method.

Sorry, but sometimes facts are just that. Your method is wrong because it doesn't work. You're giving out bad advice and I'm not looking to upset you, but folks are here asking for help.

Create this image for yourself:

Make sure the gray stripe is exactly middle gray. Make sure the gradients begin at a color darker than middle gray and end at a lighter color. Now apply your method. When you pull the Threshold slider to the far left you'll still see the gray bar -- you found it. (Click on the gray bar of the original with the gray eyedropper and you get nothing.) Note on the Threshold histogram there's a gap as you move from the gray bar to the right. Now pull the slider to the right until some part of one of the gradients shows up. Mark them for yourself and back in the original click with the gray eyedropper: you just added a color cast to the entire photo. You either find middle gray in which case clicking on it does nothing or you find a tone that is close and you have no guarantee that the tone represents a color cast. You're just as likely to add a color cast as you are to remove one.

Take Care,
Joe

 

[clanthar]

How To: Remove Color Cast With Photoshop | Photography - PopPhoto.com Offers Camera Reviews and Exclusive Photo Tips

Here ya go. While you are correct in saying this will not always work, it is a nice methodical way that doesnt require as much "interpretation" or guess work from you. Disclaimer: this does not work all of the time, but has been useful for me atleast 95% of the time.

As I noted earlier, that's the problem with the Internet... It's full of bad info.

 

[GooniesNeverSayDie11]

Actually this was printed in popular photography magazine....not the internet. Given that they own both American Photo, as well as Popular Science, their opinion holds a little more weight to me than a guy with under 200 posts on a photo forum.. I cant really do much with your previous post whereas I am not at my home comp. Unless you are using numbered values for tones when color correcting ( numbers = math = cut and dry method ) your eyeballs (manual method) is just as risky at adding a cast instead of removing one even more so if you factor that your eyes arent trained to see the slight colorcast. Therefore, if you wish to point out flaws, your entire argument is flawed. As stated, everyone is welcome to try my method. Never did I say" this is the only 100% effective way to remove a colorcast"