Luminance/Density Masking

[vogonpoet]

I have been looking for resources that cover in detail luminance/density masking techniques.

If anyone knows of any online resources or books that cover this subject, I would be really grateful. I have done some pretty extensive searching for information and cannot find any definitive information. (Maybe there isn't any?)

However, its is a subject I am very interested in and would love to learm more.

Thanks in advance for any suggestions :)

[Greg Vander Houwen]

vogonpoet,

I don't know of any "definitive information" but if you have a specific question we can probably help you out with it. What would you like to do?

Greg

[Rick Miller]

vogonpoet.

Are you referring to "The Claw": Luminosity based selections (Control/Command + Alt/Option + ~)? If so, Katrin Eismann explores luminosity based selections on page 55 of "Photoshop Restoration and Retouching". The lesson uses The Claw to correct overexposed images from digital cameras. Additionally, Jim DiVitale has a CD out that demonstrates "The Claw". This was a popular method at PhotoshopWorld San Diego.

Rick

[sPECtre]

it's maybe off topic, but I was wondering if it wouldn't be useful to have a new mode: HSL to add to the 10 existing channels : LAB, RGB, CMYK... (well, that would be 12 channels total)

Imagine, saturation based selections! ( I still need to experiment with the Claw...)

[vogonpoet]

Thanks for the replies guys.

Greg: Specifically I have no questions at this point , but its a subject I would like to study and fully explore in more depth.

Rick: Yup , never heard of the 'claw' (cept Jim Carrey did the claw in one of his movies!), but the key combo you describe is something I have seen used before to create a selection through a merge of layers. I have seen Eismanns's book on the shelf at my local bookstore, maybe its time to buy it.

Thanks again and if anyone has anymore leads/info , I would appreciate it :)

[john opitz]

Look here:

click on here (http://www.luminous-landscape.com/contrast_masking.htm)

[vogonpoet]

Thank you John for the link.

[markzebra]

Vogon - belated reply but Ive been in "no computer at home, need to get a girlfriend" for a more than a year now ;-) I just tuned in and saw this thread, and its something I work with now.

Luminance masking is a powerful technique, and a worthy question. Heres some things which you may not have ...

One thing thats not often mentioned (I think Ms Eisman misses on this one too) is the advanced blending sliders. These can be used to effectively mask areas of the layer, and are easily modifiable. The sliders here can behave in a similar way as levels would on a mask, just a different logic.

Luminosity information on layer masks is created usually by the claw method discussed or by duplicating color channels and using those as masks. Levels is maybe the best tool to modify these masks. Now with CS2 there is probably a way of using "smart objects" to create masks which are modifiable in a non-destructive way. This may require an action to create the mask from a separate "smart" document. This could just be a copy of the image.The small advantage with this would be that you could move the levels sliders all over the place without degrading the mask and creating a stepped transparency.

[MrJelly]

Spectre- I've been fudging HSL with Stroker's remap plugins- it's a real godsend for image manipulations, and saturation maps can be truly surreal.