Which is the correct way to check you work in grayscale?

[alexh96098050]

Hey good people! Ok so, I have my photo in PS, if I go to Image > Mode > Grayscale I get result A. If instead, I simply add a Black & White layer, I get result B. If instead, I simply add a fill layer > choose white or black as the color and change the Blend Mode to Color, I get result C. That's 3 different results! I can't use the first method to check my work because it converts everything, but theoretically, that is proper grayscale. So, how can I correctly check my work in grayscale if the other 2 methods that everyone (me included) says to use, are theoretically incorrect? Or am I going about this the wrong way?

[c.pfaffenbichler]

View > Proof Setup > Custom etc. 

[c.pfaffenbichler · Accepted solution]

Who (apart from you) actually recommends to preview for actual grayscale printing with a Black & White Adjustment Layer? 

4C printing has become fairly cheap so a lot of material isn’t printed with just black anymore and a 4C-black allows for deeper blacks (naturally) so maybe some people were actually talking about a b&w-effect but not actually about printing 1C? 

Save the correct Preview condition (from View > Proof Setup > Custom) and you can switch between the RGB display and the preview easily with cmd-Y (View > Proof Colors). 

[alexh96098050]

Thanks for the quick response! So I'm affraid I wasn't specific enough before. It wasn't really regarding print and such, simply speaking, when I dodge and burn for instance, I like to do it while viewing in grayscale so I don't get distracted by colors. In any case, tutorials like phlearn and most anything I viewed in the past said to use either black/white layer or fill layer. In fact a google search led me to an official adobe post that specifically said to use the black/white layer. However, I just checked out what you said about the proof colors and can say that you are right. That's what I was looking for! I just need to figure out the difference between the gamma 2.2 and sgray...if there is any. Thanks so much! 

[c.pfaffenbichler]

Sorry, I assumed the issue was about images that actually needed to be output in grayscale. 

Not sure Proof Color is really what you need but if it saves you an additional Adjustment Layer it might be useful. 

Never thought about the difference between Gamma 2.2 and sGray but a quote from 

https://forum.luminous-landscape.com/index.php?topic=101093.0

»The gamma settings are not the same (sRGB doesn't really have a gamma curve, it's a Tone Response Curve or TRC, it doesn't follow the Gamma formula). «

[alexh96098050]

Cool thanks! Regarding the proof, well imagine that in my case with retouching, there are moments when I just want to have a quick glance at how things are looking overall; perhaps I zoom out a bit, or even check contrast ecc. Before, to dodge/burn, I'd have an extra layer at the top that I would toggle on/off. Sure, the shortcut CRT+Y you showed me, is the same amount of key strokes....but the problem was that I noticed that neither the black/white nor fill layer were true grayscale. At least, if I trust image mode > grayscale to be correct, the adjustment layers weren't faithful. Instead, the proof options are. So I'm absolutely relieved. Even if it's just for my own previewing, I needed it to be truly faithful.

[D Fosse]

Yes, proof is the way to go here.

sGray is the tone response curve of sRGB - which is not a regular gamma curve. If the document is sRGB, this will be the best grayscale match.

Adobe RGB uses a regular gamma 2.2 curve, so with an Adobe RGB file Gray Gamma 2.2 will match.

ProPhoto has a gamma 1.8 curve.

And just in case you're curious, the dot gain profiles don't apply here. They are generic offset print profiles intended to compensate for ink spreading in paper, making halftone dots bigger. Nowadays they are not used, as dot gain is built into all CMYK profiles and you use "black ink - <CMYK profile>" instead.