Mask appearances

[Marpel]

Hello,

I have often used a larger size radius Paint tool (Transparency and Softness often left at default 50.0) set to black to do multiple changes to the content of a mask (to quickly erase some parts of the white portions of the mask). Occasionally, I have noticed some faint "bleed through" on the resultant image when using the mask in the Composite Transform (Blend mode) when blending two images, indicating I was not diligent enough when erasing some portions of the mask. No big deal to solve as I just started moving the default 50.0 to the far left side (don't have PWP open and can't recall if it is 100 or 0) to get a hard edge to the radius. Although, when in a hurry and doing multiple masks I occasionally forget this step.

However, I happened to try to use a PWP generated mask (in which I used the above noted 50.0 setting) in Photoshop and was surprised to see some white, albeit faint but visible, in the black areas that I thought I had erased, through using the Paint tool. Upon closer inspection and comparison, I discovered that I could see the faint white marks in Photoshop but could not see them in PWP (even at significant zoomed in view). Of course, these white marks match the noted bleed throughs. I used the same Monitor and conditions to view in both programs.

Can someone advise why Photoshop seems to show these marks better than PWP and is there a setting in PWP that I may play with to make these marks clearer so I don't have to move the mask into Photoshop to confirm I fully erased the intended whites? Even though they are very faint, they do make a visible impact on some blended images. I wouldn't be surprised if Photoshop and PWP rendered some colours differently but am confused why it would do so with black/white tones in this way.

Thanks

Marv

[Dieter Mayr]

Hello

I do not find time for testing much now, so just some quick thoughts.
Photoshop has a setting for Working Colorspace for Black and White, maybe it is set to something unusual.
Photoshop has a default white background in the working area, PWP a dark gray, maybe this has a optical effect.
I dont know if Adobe tools like Adobe Gamma affect only Adobe programs of others too, may be a point to have a look at, too.

Maybe it helps

Dieter

[Dieter Mayr]

I have made a screenshot of a Mask-like image (8-bit BW) both in PWP and PS, side by side.

BWAppearance.PNG (29.67 KiB) Viewed 6740 times

Painted with settings for Transperancy and Softness are the default 50%
Here it looks like the PS-Version is slightly darker, and a measurement with the readout tool gives a minimum value of 6 in the PS-Version and 14 in the PWP version.

[Marpel]

Hello Dieter,

Thanks for your two responses.

Regarding your first message - I don't think this is related to any unusual settings in Photoshop, as when just viewing the mask, Photoshop actually shows the light tone on the black background, which I suspect is as a result of the remnants of the outer edges of the blurred paint tool (as shown in your second post) where I did not completely paint out a white area of the mask (leaving a faint darker grey mark on the mask). The effect of these missed spots can be seen in the composited image, especially if the two source images had contrasting colours where the "bleeding" occurred. So I suspect that Photoshop is actually showing what is there while PWP is not. This same logic leads me to believe the optical effect that you also suggest, is not occurring. Unfortunately, I don't know enough about Adobe Gamma to even figure out if that may be part of the equation.

Regarding your second post - The example picture you provided is exactly what I was referring too regarding the blurred edges of the paint tool and I suspect the faint greyish marks, visible by Photoshop but not by PWP, occurred near the outer edges of the tool where the transition from white to black is faint and I was not complete when removing the white in the initial mask. As stated in my initial post, to eliminate the problem I can either use a radius with a hard transition or repeatedly go over the area to ensure all white is eliminated. I do a lot of quick masking, however, and occasionally forget to do either, thinking I captured everything (because it looks black, of course). Unfortunately, I am not sure if your example and the difference in readings actually supports what I have seen as some of this is over my head.

Thanks again for your input,

Marv

[Dieter Mayr]

I have made another Test now.
Creating a pure red and a pure green image plus a mask created with paint consisting of 2 overlapping circles, one pure black (0/0/0) and one made slightly brighter step by step.
When I start to see a difference in the "blacks" of the circles, which happens on my system at a decimal RGB value of 8/8/8 I also start to see a diffence when overlapping the red and green image with use of the mask.
When I open the mask in Photoshop, I dont see a diffence there, this confirms my first test that on my system the display on PS is slightly darker then on PWP.
Both systems are fully color managed, both using the same monitor profile.

Adobe gamma usually playes itself in the Autostart folder of windows and can be found in the Autostart entry in Start - Programs.
It's a tool to manually create some kind of monitor profile, if you use a colorimeter to create a monitor profile, Adobe Gamma should be deleted from Autostart.
I am not sure if the settings of Adobe Gamma have the same effect on PWP as they have on PS, I run a fully Color manages system for many years now and have never dealt with Adobe Gamma.

Hope it helps

Dieter

[jsachs]

Are you using the same mask file with both programs or are you generating the masks by hand separately for each program? If so you may be measuring differences in the mask tools and not differences in the displays.

[Dieter Mayr]

The mask was created by hand in PWP (New image, 8 bit, the circles drawn with Paint tool), saved as TIFF and opend in PS.
The mask in the first example was created and transfered to PS the same way, the measurement was done on a screenshot in PWP.

[jsachs]

OK good, just checking.

[Marpel]

Dieter,

Thanks for looking into this further. Interesting point about Adobe Gamma and its potential conflict with a profiled monitor using a colour meter. I have been using a colour meter on my NEC monitor for quite awhile (and on the monitor I had prior to this) and don't recall reading any mention of deleting Adobe Gamma from autostart in any literature about monitor profiling (although I must admit it has been awhile since I tackled that subject). Having said that, if you have a fully colour managed system with Adobe Gamma deleted and you see a difference between the two systems, wouldn't that indicate that deleting Adobe Gamma would not change my system to where both programs viewed the same mask the same way?

Marv

[Dieter Mayr]

I dont know exactly what Adobe Gamma does internally, if it provides something for Adobe programs that is not available not for other programs.
I use the Color Mechanic Monitor tool for calibrating my Monitor and in the manual (which is unfortunately not available for download anymore) Jonathan writes about Adobe Gamma and to disable it before any calibration action.
I dont know enough about handling Black and White images internally to try a explanation why the difference i see occurs.
I tried various setting in PS monochrome profiles, the values of the almost black field did not change.
On the other hand, when trying the same with a color image, creating in PWP with pure red, green and blue fields, saving as TIFF, opening in PS, both systems set to the same Working CS, making a screenshot, measuring the values, gives exactly the same values for all 3 colors.
PS must do something slightly different then PWP to display BW images.