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Discussion Starter · #1 ·
I couldn't find much on here or anywhere about this. I picked up a NuArc 40-1K Mercury exposure unit. I have been doing exposure test times all weekend and coming up unsatisfied.

It seems that it runs in light units and from my testing each unit is 10 -12 seconds, With the exception of the fist unit that seems to turn after 6 seconds.

I have exposed a 156 screen 3 times now and I have not had luck with the washouts. It either washes all out or it does not.

The exception was last night. At 2 minutes it washed out fine but the small dots did not seem to stay on the screen. I am thinking maybe they were too small? I found an exposure test online and the download was 8x11.5.

So each test strip on the page of 10 tests was only an inch high by about 7 inches long. So the gradients got really small.

I think if they were larger I would have better luck. I have never printed gradients and want to start a new skill set in printing.

What is the smallest gradient I would probably print? Does it sound like my test strip was way too small? I think I should be using 4 sections on the screen to test but can not find a test large enough.

If I make sense because I confuse myself with this, Please help! :)
 

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Do you know the LPI the step test was output? On a 156 it should be 30-35 LPI playing it safe. You can't resize a halftone that has already converted from grayscale.

I don't have that exposure unit but I use the same bulb. Btw the best place to get replacements is Bulb America, Ushio 1200w $36. These units are best for photopolymer due to the spectrum they peak in but work well with diazo dual cure also.

Do you have simple seps 3? Or a Rip. You can always do the conversion in graphics program but results are best with either of the above. I made a step test I have uploaded to afew threads. I can up load here when I am at PC if needed. If so let me know your print size and mesh if you need it halftoned.
 
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Discussion Starter · #3 ·
I do not know the LPI but this is the test I downloaded.

FREE Screen Printing Exposure Calculator

I am using SBQ poly. pre sensitized .
I also have separation studio.
Fast Films 3.5
And I do have knowledge on how to split channels and create half tones in Photoshop.

I am better at Photoshop than running those programs. I only have a 4 color press so usually those programs produce more colors than I can print.
I am seriously thinking about getting AccuRip but I do not know if it would be any better than what I have?

If you wouldnt mind uploading I would love to try a burn on it. I use 20x24 screens

Thanks for the bulb link. I have seen them on Ebay also for about the same. It came with two bulbs, So I hope I am good for a little while.
 

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I do not know the LPI but this is the test I downloaded.

FREE Screen Printing Exposure Calculator

I am using SBQ poly. pre sensitized .
I also have separation studio.
Fast Films 3.5
And I do have knowledge on how to split channels and create half tones in Photoshop.

I am better at Photoshop than running those programs. I only have a 4 color press so usually those programs produce more colors than I can print.
I am seriously thinking about getting AccuRip but I do not know if it would be any better than what I have?

If you wouldnt mind uploading I would love to try a burn on it. I use 20x24 screens

Thanks for the bulb link. I have seen them on Ebay also for about the same. It came with two bulbs, So I hope I am good for a little while.
here is a editable PDF in vector and is 13X19 so if you resize the scale would be off and do so before halftoning if you need to output to a smaller size. If your using 156 set the LPI no higher then 35 until you can accomplish that as a good exposure The test is only 3 steps. Once you comfortable with halftones you can push the LPI further.

if you want to compare to a pre halftoned test out of Corel let me know the size you will be printing
 

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Discussion Starter · #5 ·
wow, Thanks. This is great and I will try it this week!
Instead of a new topic can I ask a question off topic?

I am using photoshop/color range tool on a three color job. The design is a circle in a circle, Like a target . So there is text on the first ring. The middle is hollowed out and there is an image in that.

The black I want to expand as a trap. ( There will be a white base on the dark GIs ) But each time I expand the strangest thing happens. The text area expands but the center image contracts. I keep doing it over and over and can not understand why this happens? Why wouldnt it just expand the entire black part of the design 1 px ? Image attached.

The black band expands. The surrounding area around the text expands. The dragon contracts.
 

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I think I understand, what I would do is separate into Channels first, then add chokes or traps separately by using the magic wand or the marquee tool.

Its rare any more for me to use photoshop. So someone else may have a better way. Ever since Adobe made some changes a few years back I switched to Corel. I would have vectored that, the assigned Pantone colors and Corel will auto separate that and add traps automatically from the separation tab.
 

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Discussion Starter · #7 ·
They are separated into channels. It is a lot of work in photoshop. Maybe I better find an alternative. I must have tried for 2 hours and kept getting the same result. I tried selecting with the wand tool, separate from the other parts but it wants you to save selection after you do a piece and then it saves a new channel. Just a big pain.

I gave up on this design and will just get the lines as close as possible on press. I should be okay . I was able to get the expand on the dragon at least.
Thanks again

I will try Corel. Just have no experience in it.
 

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I think I understand, what I would do is separate into Channels first, then add chokes or traps separately by using the magic wand or the marquee tool.

Its rare any more for me to use photoshop. So someone else may have a better way. Ever since Adobe made some changes a few years back I switched to Corel. I would have vectored that, the assigned Pantone colors and Corel will auto separate that and add traps automatically from the separation tab.
Sean I am still new to this , could you explain the trapping in corel , I an not familiar of how it works.
 

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Sean I am still new to this , could you explain the trapping in corel , I an not familiar of how it works.

All your colors have to be Pantone and vector to use the auto seps and auto trap. You also have to output to a post script file and then print. I have added a few pics. there is a few web sites that have the entire process from start to finish. I have everything set and would hate to not give the full instructions
 

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Discussion Starter · #10 ·
I was able to do this in Corel. Not the way you explained, So I must learn it proper. But it was easier than all the other things I have tried the past two days! I will be watching tutorials on this program. BY the way have you ever tried Pixel Splitter by Steve Yates?

It looks like it separates everything and can do Half tones. Its under 150.00
 

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As long as it gets the job done its the right way. There is multiple videos out there for using the auto seps and trapping I don't think any of them are identical. I have pixel splitter, simple seps, tseps, ultra seps. The best for vector and monochrome/duo chrome bitmaps is simple sesp. The halftone output is about identical to accurip or Filmmaker(if I turn off variable dot in Filmmaker) it has a convert to Pantone function in it that is very valuable. It also has a option for printing Rich black or all black for dark films. I used to manually change everything to 100% CMYK for all black and then Tom added that function

The photoshop plugins simply use the halftone conversion action in Photoshop.
 

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Discussion Starter · #12 ·
I really like how Corel works. I have been using Photoshop and Illustrator for 10 years and It always seems I am looking for a tutorial on how to do something. I started this up and and basically learned what I needed to know in an hour. Unreal.

There is an issue though. Still with Reg marks. As you can see I made my own Reg mark. It shows as its own layer when I go to print and then it is not on any of the other seps.

Also, Still when I use the reg marks built in the print program it comes up as an issue saying it wont fit on media. No matter what size I print it wont show.

How can I get my own reg marks to show on all the seps?
 

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Make a copy of the reg marks for each color and make them that Pantone color so if you have a 3 color job you would have 3reg marks one of ea color


The reg marks in Corel I don't like but you have to click print preview, click the reg mark icon the drag them into view on the page.
 
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Discussion Starter · #16 · (Edited)
Thanks I will try this. I am trying to use the reg marks in the print screen, but It doesnt work when I drag them or click them. I dont get it..
EDIT
I dont mean to sound thick headed, I just am! But once I get this I will be good to go.

I have a design 3 color.
I made my own reg marks.
I locked them to the page/ and saved them as a template

Why cant I take the page as it is, all three colors with reg marks. Go in to print screen, ( select print seps ) and have that locked layer show up on all screens?

You said, I had to change the color of my reg marks for each color printed, But how?
Do I have to make a new page for each color?

If so, How do I get them to all come together so they print one screen?
 

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Thanks I will try this. I am trying to use the reg marks in the print screen, but It doesnt work when I drag them or click them. I dont get it..
The Registration color works. Cant believe I never knew that Thanks Jim

The corel reg marks you have to click the print preview the click the 3rd Icon down (reg mark) you may have to zoom in the first time but the red line represent the reg marks. drag them to the image. I sometimes use both the corel and mine on tight registration jobs
 

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Discussion Starter · #19 · (Edited)
When you select it to overprint the black, How much does it over print? Is it best to just do it yourself before print?

and last question on this matter..

Print options.
What is the post script? Everything looks great, But I do not know how to use it or print to my Epson with it.
If I select my Epson everything is out of whack. No longer Mirrored.Reg marks off, even the way it looks and fits on print screen.
 

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If you don't have any halftones you can simply print directly to printer as usual. I'm not sure why things are changing. Try opening the post script in Illy I didn't look at the post script options to see where min are set I think from the printer options mine is set to print in center of page.

The overprint on black I don't use. I usually butt print black. A lot of times since black is so thin and doesn't affect other color prints I will print it first to maintain nice sharp edges but if you trap the other colors too much it can shrink your black if printing it first.

You will find everyone has their own techniques and preferences. I myself was a long term Adobe user from the early 90's. When Adobe took out the screen button and a few other features in CS5 I switched to Corel and never looked back. I still use photoshop occasionally especially since I have the simple seps raster for photoshop so I revert when doing raster occasionally.
 
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