Calculations/Advanced Channel and Mask Combining

[tranquil222]

OK, I got this technique from The Photoshop Bible. First off, i'm assuming you know what masks and channels are. Here we go. Lets say that you have two channels/masks that intersect each other at some point, as in fig. 1(a photo is not the best example, as I had to guess where the shapes, were, but other applications may be better suited). How do you combine them into one channel? With calculations(which ive finally found this use for it), how can't you? Calculations a little known tool in the Image file menu. In a nutshell, what it does is it takes two channels and combines them into one, and gives you many blend modes and options along the way. Ok, so you have your 2 channels all ready, as in the middle of fig. 1. Go to Image-->Calculations. This box gives you three sections. Your source 1, your source 2, and how you want to blend them. Mixing these can let you simulate the add, subtract and intersect functions. But what really grabs me about this, and I really wouldn't care about this option otherwise is the fact that it gives you THREE more combo options to choose from: inverse&add(IN THE CALCULATIONS BOX: invert top source(check box to the right of option), set blend mode to screen), exclude(just choose difference blend mode), and exclude&inverse(invert the top and choose the exclude blend mode), shown in fig. 2. These combos are not too easy to do otherwise without some manual workarounds, so this technique can really come in handy.

[Erik]

How one nugget can turn into yet another goldmine...

thanks for sharing!

[tranquil222]

Oh yes, once you are done, it creates a brand new, separate, channel. Calculations does not change the pixels in your image: you can choose from three options for your result: a new document, a new channel, or a selection(<----this is the one i used for the above excercise).

[wbiss]

B7 Too cool tranquil222! I'm going to have to play around with this for sure, as it's totally new to me! ;)

Tx for sharing! [excited]

[ljiljana]

tranquil222 ,

Yes,those are great.
I learned from Kai`s Power tips and tricks: secrets of chops ( channal operation).

[tranquil222]

Is that a book or a website??

[namvet]

tranquil222 .. it's a page on a website (pixelfoundry) ... link to the tips page is at ... http://www.pixelfoundry.com/Tips/ ...

ljiljana ... that tips page is real interesting ... geesh, you get around ... do your feet ever touch the ground??

[wbiss]

;) Tx for posting that link Ian (namvet)! B7

[ljiljana]

tranquil222 .. it's a page on a website (pixelfoundry) ... link to the tips page is at ... http://www.pixelfoundry.com/Tips/ ...

ljiljana ... that tips page is real interesting ... geesh, you get around ... do your feet ever touch the ground??

Thanks , Namvet. ;)
First I got tips from Gurusnetwork.com : they had a permition to host a copy of invaluable Kai`s Power tips...