Author Topic: Choking underbase in photoshop  (Read 5700 times)

Offline 3Deep

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Choking underbase in photoshop
« on: September 24, 2020, 11:23:55 AM »
Can some reteach me about choking a white underbase in photoshop, been a while  since I've done manual seps in photoshop.
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Offline Frog

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Re: Choking underbase in photoshop
« Reply #1 on: September 24, 2020, 11:37:28 AM »
Wouldn't one way be to simply add a stroke of a different color?
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Offline ebscreen

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Re: Choking underbase in photoshop
« Reply #2 on: September 24, 2020, 11:49:34 AM »
If base channel is already made, load it as selection (ctrl+click channel)
select->modify->contract by whatever you want. Select->save as new selection.

PS gets weird with inverting selections in a manner I still can't figure out, so if
your new base channel saves as inverse just deselect all (ctrl-d) select the channel and hit ctrl-i.




Offline Nation03

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Re: Choking underbase in photoshop
« Reply #3 on: September 24, 2020, 12:09:48 PM »
If you do things in Layers and not channels this is how I do it.

Right click the layer you want to choke, click select pixels, then go to top and click Select > Modify > Contract. Enter how many pixels you'd like the choke to be and then you can cut the layer and delete the excess outline.

At least that is how I do it, I'm sure there are other ways but this has always worked for me.

Offline Sbrem

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Re: Choking underbase in photoshop
« Reply #4 on: September 24, 2020, 12:17:53 PM »
Though I do channels, it's pretty much the same for layers, you're selecting the image, NOT the background, and then Select, Modify, Contract... how many pixels contract is determined by your image resolution. At 300 ppi, I contract 2 pixels...

Steve
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Offline 3Deep

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Re: Choking underbase in photoshop
« Reply #5 on: September 24, 2020, 12:53:42 PM »
If base channel is already made, load it as selection (ctrl+click channel)
select->modify->contract by whatever you want. Select->save as new selection.

I pretty much did it this way, just wanted to make sure I was correct, thanks guys

darryl
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Offline Sbrem

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Re: Choking underbase in photoshop
« Reply #6 on: September 24, 2020, 02:09:44 PM »
all I'll add is one more click; I assumed the image is black and the background white in that channel, so after contracting, I invert my selection, so that now the background is active, and fill it with white. You'll notice it trims the black image. An important step to leave out, sorry...

Steve
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Offline ebscreen

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Re: Choking underbase in photoshop
« Reply #7 on: September 24, 2020, 03:36:48 PM »
Attached is a PS script I wrote that will automatically create a choked base from all channels.

If the channel is named "White" is will add to base but not choke.

If the channel is named "Blk" (stupid PS/Illy color name conflict issue) it will not add it to the base.

Offline ZooCity

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Re: Choking underbase in photoshop
« Reply #8 on: September 24, 2020, 04:45:58 PM »
If base channel is already made, load it as selection (ctrl+click channel)
select->modify->contract by whatever you want.

Same up to here.  Then I select inverse and delete that data from the original base channel.   I do what you do if I'm isolating something to a new layer for a different amount of choke.

Can't wait to try the script, does it use calculations?

Offline Sbrem

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Re: Choking underbase in photoshop
« Reply #9 on: September 24, 2020, 05:24:05 PM »
Attached is a PS script I wrote that will automatically create a choked base from all channels.

If the channel is named "White" is will add to base but not choke.

If the channel is named "Blk" (stupid PS/Illy color name conflict issue) it will not add it to the base.

So, that's when there is no base white yet, yes? That's pretty much how I do some of them, I never thought to make an action of it though, cool.

Steve
I made a mistake once; I thought I was wrong about something; I wasn't

Offline ebscreen

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Re: Choking underbase in photoshop
« Reply #10 on: September 24, 2020, 05:52:17 PM »
If base channel is already made, load it as selection (ctrl+click channel)
select->modify->contract by whatever you want.

Same up to here.  Then I select inverse and delete that data from the original base channel.   I do what you do if I'm isolating something to a new layer for a different amount of choke.

Can't wait to try the script, does it use calculations?

PS has always weirded me out with deleting. Sometimes it deletes everything selected, sometimes percentages based on the selection.

This script is a part of a larger one I wrote for a bigger client of ours that send the same type of formatted art, which made
scripting mockup/seps super easy. Of course I've promptly forgotten how any of it works which is how I roll.
I do know that Adobe has some funk when it comes to what is essentially javascript, and the same rules do not always apply.




Offline ebscreen

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Re: Choking underbase in photoshop
« Reply #11 on: September 24, 2020, 05:53:44 PM »

So, that's when there is no base white yet, yes? That's pretty much how I do some of them, I never thought to make an action of it though, cool.

Steve


That is correct. Found myself doing the same exact action 20 times a day so decided to sit down and learn how to script it.

Offline ZooCity

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Re: Choking underbase in photoshop
« Reply #12 on: September 24, 2020, 07:30:58 PM »
I too have noticed weirdness when deleting.  Also with applying the Threshold adjustment.