Mask appearances

[jsachs]

PWP does not color manage B&W images. What happens if you convert the B&W image to color and then compare the displays?

[Marpel]

Jonathan,

I just converted an 8 bit mask to 48 bit colour and compared both versions in Photoshop and PWP with the following results:

8 bit - Markedly more visible in PS than in PWP.
48 bit - More visible in PS than in PWP, but far less than the 8 bit.
8 bit compared to 48 bit - In PS, the 8 bit image is quite a bit more visible than the 48 bit. In PWP, because the faint white portions are very hard to see in either image, it is hard to tell, but there is a bit of a difference between the two.

Marv

[jsachs]

In that case, it's probably related to color management of B&W images in Photoshop. I'm not an expert on PS color management, but you might check your PS Color Management settings to see what it is set to do for grayscale images.

The color management engines in PS and PWP are similar but not identical so I am not surprised you are seeing some minor differences in the color images.

[Marpel]

Thanks,

I will check my PS settings as suggested. However, as indicated in my initial post, it is PWP that seems to be less precise (for lack of a better word) as when two colour images are composted together (blend mode) using the mask, I can see some ghosting in the resultant colour image, specifically where the the faint white areas of the mask are visible in PS. This colour ghosting is visible in both PWP and PS. I guess I'm wondering if I have not set preferences correctly in PWP or if this is just something inherent in PWP.

Marv

[Dieter Mayr]

Measuring a sreenshot of both the monochrome (8 bit) and colror(24 bit) version of my test image.
Both color images in sRGB, both Working CS are sRGB
Values measured in the screenshot:
PWP 8-bit measured 16
PWP 24-bit measured 16
PS 8-bit measures 8
PS 24-bit measures 10
Alll above measures are taken with Adobes ACE and lcms as color engines.
Both programs set to Microsoft ICM gives the following measures:
PWP 8-bit measured 14
PWP 24-bit measured 14
PS 8-bit measures 16
PS 24-bit measures 11
So there are slight differences even using the same color engine.

Marv, can you post a small portion (maybe 200 x 200 pixel crop) of a area that makes problems from your mask ?
I have made some masks the way you described and when i have visible "bleeding through" I also am able to see the defects in the masks.
So it would be interesting to have a look at your masks.

[Marpel]

Dieter,

I find it interesting that PWP remains consistent between the 8 bit and 24 bit versions while PS shows a difference between the two.

As to posting a smaller version of the mask - I am quite agreeable to having you take a look however I am concerned that you will have difficulty seeing the difference with a small image. I would prefer you look at the same sized image that I am so would rather send you a full version via e-mail if you are agreeable. As I don't know your email address, you can forward it to me at marpel@shaw.ca and I will forward the mask with an explanation as to what and where I see the ghosting.

Marv

[jsachs]

In PS, under File/Color Settings..., what do you have selected for "gray" working color space. The default is 20% dot gain which will make very dark grays black in B&W images. Changing to Gamma 2.2 should make B&W images more or less match sRGB.

[Dieter Mayr]

Marv, I have send you a mail.
Jonathan, the gray working CS was set to Gamma 2.2

[Dieter Mayr]

Marv, i have recieived your image.
On my system the not full black area is better visible in PWP then it is in PS with Gamma 2.2 as working CS.
Setting PS to DotGain 20 gives about the same visibility then in PWP.
Can it be that you have a monitor curve active in PWP that dims down the dark colors ?
I am running out of ideas ....

[Marpel]

Dieter,

I am sort of glad that you see something different than I do as it suggests that I may have something screwed up at my end rather than a problem inherent to PWP. However, I am not aware of a monitor curve specific to PWP. I have an NEC monitor that is set up with Spectraview and a colour meter puck but that should be consistent between all programs (at least from my relatively limited perspective). Perhaps my PWP colour settings are affecting the generic monitor profile?? I believe, if memory serves, that I followed some suggested settings (PWP help, tutorial or white papers??, can't recall for sure). I will have to take a look at that process again.

Anyway, thanks to you and Jonathan for all your help.

Marv