Author Topic: HOW TO GET RID OF THE UNDER 5% HALFTONES?  (Read 6795 times)

Offline Rockers

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HOW TO GET RID OF THE UNDER 5% HALFTONES?
« on: May 03, 2015, 09:22:52 PM »
As Photoshop is not really my choice of software for seps I really have no idea about how to do certain things that are essential for sim process jobs for example.
For example I would be at loss if I had to make adjustments to my greyscale or sim process files so that we don`t print the kind of halftones we can`t hold anyway onto film.
And this might sound now like wishful thinking by me, maybe someone could give me some detailed instructions on how to do this, ideally with some screen grabs so I know what tools to use and how to use them?
Would be a real big help.


Offline Homer

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #1 on: May 04, 2015, 08:03:12 AM »
adjust the levels. it's up under adjustments in PS, the slider all the way to the left, move it to the right a few clicks...should knock out the lower %..


buy Mitch Different's book on seps, you'll really like PS after, tones of great info.
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Offline Denis Kolar

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #2 on: May 04, 2015, 09:04:16 AM »
Go to the curves, make adjustment layer (Never adjust directly on the file because you can not reverse it if saved) and move the bottom of the curve from 0 to 5.
That will make all the dots smaller than 5 to be at least 5%.

Offline Sbrem

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #3 on: May 04, 2015, 11:20:14 AM »
Go to the curves, make adjustment layer (Never adjust directly on the file because you can not reverse it if saved) and move the bottom of the curve from 0 to 5.
That will make all the dots smaller than 5 to be at least 5%.

However, this means that the 2% or so is raised to 5%, instead of being removed. It's a scrunching of the range. Some may find it too dark... Where's Dan on this topic?

Steve
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Offline jvanick

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #4 on: May 04, 2015, 11:28:55 AM »
also be careful with 100% pure white sections that aren't transparent... sometimes (and not really sure when, but it's happened to me) when you do the adjustment the 0% will get raised to 5% as well, which is probably not what you're looking for.

Offline Denis Kolar

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #5 on: May 04, 2015, 11:51:57 AM »
Go to the curves, make adjustment layer (Never adjust directly on the file because you can not reverse it if saved) and move the bottom of the curve from 0 to 5.
That will make all the dots smaller than 5 to be at least 5%.

Nevermind this. I understood the question the wrong way. You have to move the curve horizontally from 0 to 5.
See attached

Offline ScreenFoo

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #6 on: May 04, 2015, 12:01:30 PM »
Actually, you need two points--one at the 5% in, 0% out point, and one at the 5% in, 5% out point--otherwise, you're just starting 5% @ 0%, which will still result in 1-5% tones...


Offline Gilligan

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #7 on: May 04, 2015, 12:10:27 PM »
Another way would be to use the levels and adjust your output then mid point, like so.

I pulled up a gradient and played with it to try and keep the over all feel the same... I'd suggest you do the same so you know what is going to happen to the overall tonality of the image when you do this.


Offline Sbrem

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #8 on: May 04, 2015, 03:15:23 PM »
If you simply move the bottom left point to the right, all other tones are also lightened. Draw a set of boxes in 5% increments (say, 5% to 20%). Move the slider as suggested, then measure the boxes; you'll find the the 10% is now 5%, the 15% is 10%, and the 20% is now 15%... I believe you need to lock the diagonal line in the Curves pallet by placing points along the diagonal line before you move the bottom left to the 5% mark, this keeps the others from moving, and they should stay the same or very close.

Steve
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Offline Sbrem

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #9 on: May 05, 2015, 04:28:50 PM »
UPDATE: OK, this is cool, try it. Open the Curves dialog, we are going to use the "pencil". In the bottom left of the curve box, hover your mouse over the diagonal line, it will tell you what percentage you're on. Click and hold at 5%, drag straight down, and then all the way to the left. All tones 5% and below are gone, and nothing else is affected. Obviously, you can choose any tone as your starting point. I tested with a 0% - 100% grayscale bar in 5% increments, and when I did it, the 5% box just disappeared. Hope this helps...

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

Offline Colin

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #10 on: May 05, 2015, 05:18:28 PM »
UPDATE: OK, this is cool, try it. Open the Curves dialog, we are going to use the "pencil". In the bottom left of the curve box, hover your mouse over the diagonal line, it will tell you what percentage you're on. Click and hold at 5%, drag straight down, and then all the way to the left. All tones 5% and below are gone, and nothing else is affected. Obviously, you can choose any tone as your starting point. I tested with a 0% - 100% grayscale bar in 5% increments, and when I did it, the 5% box just disappeared. Hope this helps...

Steve

Yep This.
Been in the industry since 1996.  5+ years with QCM Inks.  Been a part of shops of all sizes and abilities both as a printer and as an Artist/separator.  I am now the Ink and Chemical Product Manager at Ryonet.

Offline Gilligan

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #11 on: May 05, 2015, 05:25:40 PM »
Nice.. I thought this had to be possible!

Offline ZooCity

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #12 on: June 16, 2015, 03:18:59 PM »
Great thread.  It made me dig down and learn curves a little better.  High time considering I use it every day. 

What about curving out those 85-99% values on the other end?  I know this is where a good rip really kicks in but for those without or using Accurip where the linearization does not function correctly it'd be nice to pull back that area to comp for the gain.

Offline Colin

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #13 on: June 16, 2015, 06:13:44 PM »
Chris,

Do you need to compensate for gain through the rest of the tonal area? 

Or are you JUST looking to open up your shadow areas?
Been in the industry since 1996.  5+ years with QCM Inks.  Been a part of shops of all sizes and abilities both as a printer and as an Artist/separator.  I am now the Ink and Chemical Product Manager at Ryonet.

Offline ebscreen

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Re: HOW TO GET RID OF THE UNDER 5% HALFTONES?
« Reply #14 on: June 16, 2015, 06:25:42 PM »
Personally if we can't expose/develop/print them, I don't wanna see them on film.

Great info Steve.