problem with curves shadow eye dropper applying mask

[Richann]

Hi all at Retouch Pro....first time poster here....only checked out this forum for the first time the other day....it seems very active and informative and I am looking forward to being active here also. I have recently begun a part-time apprenticeship restoring photos and I have begun dabbling with other similar digital venues.

Any ways, here I am already asking for help...why, not? lol

I have recently been taught, using Photoshop, to use the threshold to find and mark and image's darkest shadow and whitest highlight. Then, for color correction to use curves. I select the highlight eye dropper and click on the lightest highlight in the image and then use the shadow/dark point eyedropper and click on the darkest point on the image.....the problem is

...........that recently Photoshop started applying a red mask when I go to click on the darkest point in the image using the shadow eyedropper....what gives?.....I have asked my mentor, check the photoshop bible and some Photoshop seminar booklets and have not found out what is going on or how to correct it....does any one here know....I was considering just reinstalling Photoshop but thought I would check here first.


Thanks,
Richann

[Doug Nelson]

By any chance is red selected as your gamut warning color? Edit>Preferences>Transparency & Gamut

[Richann]

No, grey is selected.

[Doug Nelson]

Hmmm....how about if you click on Options in the Curves dialog box. Are any of the three target colors red?

Try holding down the Alt key and selecting Reset (where the Cancel button normally is).

Also, try doubleclicking on the eyedropper and verifying that it's set to R0,G0,B0.

Is this something you can provide a screencap for, so we can see?

[Richann]

Thank you Doug. The dark point was not set right. You said, "Also, try doubleclicking on the eyedropper and verifying that it's set to R0,G0,B0." that was the answer. My dark point was set to red. Thanks again!

Richann