Hi folks.
Anybody knows how to increase the opacity of a pixel (without altering it's RGB values) ?

It's just soooo BASIC that I fear I'm overlooking something incredibly obvious.

To make it really clear: I have a pixel with, let's say with RGB=(48,33,57) and 25% opacity. How can I make a (48,33,57) pixel with 75% opacity out of that ?

I find, right after the brush tool, that's the most obvious tool for Photoshop. I wonder, why this is missing !?? Most tools have their counterparts, like dodge/burn or sharpen/blur. So why does the eraser (decrease opacity) don't have a counterpart (increase opacity) ??

Thanks so much.

((PS: And as I know the question will come: No, I don't mean layer opacity. The layer has 100% layer opacity and 100% fill opacity.))

Use a layer mask.

This is the typical non-destructive way of altering opacity in Photoshop. This will give you the counterpart to an eraser that you are seeking - - but the trick is to stop using the eraser.

Thanks Jim. Of course I know layer masks. I use them whenever I can. But sometimes I work on source material with a transparency/alpha-channel, like a partially transparent .png etc. At this point it's too late for a mask.

I just can't believe that this most obvious tool doesn't exist in Photoshop!??

Any workarounds? Or anybody who can recommend me another software which would help me in that regard ?

Thanks a lot!

At this point it's too late for a mask.




The mask is there. Just ctrl-click on the layer icon (load selection... layer transparency), make a new channel and fill with white. Then you can use the peel off white filter <http://www.adobeforums.com/webx/.3bc34571> to regain your "original" RGB values (on the RGB layer).

Finally, apply the original mask you saved, and edit it as Jim describes. Obviously, you'll have trouble guessing what color white/trans pixels were. In comes the art part.

J

JMaloney,thanks so much for helping. I'm halfway through your steps. Your first part is basically the same as ctrl-click the layer and save the selection.
I still have to read through those third party filters ...
With the function PS provides itself, this is not solvable ?

In place of running the filter: you could duplicate the layer 4 times, merge them, duplicate 4 more times, merge them, 4 more times, merge them, etc. I think I did 4 iterations of five and then duplicate number two on round five was done (all pixels either fully opaque or trans). I have no idea about the math on this. None. But its actionable!

The filter (Alphaworks for PC) is freeware, tho... I'm kind of assuming it works like Peel off white on the Mac...

J

You can access tranparency directly in Photoshop, via the Filter Factory, which ships with Photoshop, but is not installed by default (it's in a folder called 'Goodies' on the 'Extras' disc, IIRC).

Select which pixels you want to affect, and run the Filter Factory (it'll be under 'Synthetic'), using the value in the 'A' field to control the transparency. You can use a simple numeric value, or a formula, such as "a<128?128:a", which sets the transparency (opacity, really) to 50% if it is less than 50%, otherwise leaving it as is.

There is an important issue with a "Feature" of Photoshop's transparency: if, by any means, a pixel has been set to completely transparent (the value in its Alpha channel equal to zero), its original color value will be stripped out, and replaced with the current Background color, which will be seen when opacity is restored.

Wow, J Maloney and John R Nielsen, what you are saying is gold for me!

J Maloney, your approach is so simple but yet so creative. Incredible! I'm sure it works. How do you know actually that all pixels are 100% opaque ?

John, thanks so much for your directions. Seems very promising. Thanks also for the warning you issued. Is the "Filter Factory" you are talking about the same as this here: <http://www.photoshop-filters.com/html/filter_factory.htm>
?

Unless the bosses have a better solution, they shouldn't roll their eyes, me thinks

OK, I see, so you decide visually if you are done or not. Actually, I'd love to have a transparency channel for the pic, so that when you click on it and the whole picture turns white, you know that all pixels are 100% opaque. It would be so easy for Adobe to implement this. Wonder why they don't deem it helpful/necessary ?

Select>Load Selection>Layer Transparency. Quick Mask mode. Check the Histogram.