Author Topic: Free downloadable halftone test file  (Read 8017 times)

Offline Dottonedan

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Free downloadable halftone test file
« on: December 09, 2014, 11:46:17 PM »
Here's a good test file to determine what you are actually holding in print.

I suggest printing it using your device of choice, and then printing in black ink on a white garment material at various halftones. 45, 55, 65 etc.

The goal should be to hold at least the 5% dot and in the area of 94-97% shadow dots in print.

If you are holding better, then you're on point. If not, then something is not aligned in your process accurately.

NOTE, before you expose and print, (check the images) to confirm you are actually containing that information in your films or on DTS. If not, (if your shadow dots area already filled in at lets say the 80% range for example, then you are losing some art information before you ever start. That is a problem.

You need to adjust your tonal range output (for your device) aka, dot gain compensation...so that you are getting some information out onto your device in those areas. In the best case scenario, you would use a reflective or transmissive densitometer for accurate measurements, (and adjust again to compensate) on films/dts and then read it again on press... but most don't have that luxury. If not, as long as you have "some halftone content" in there and as small as you can get it (down to the 99% range), the better off you are.

No two adjustments will be identical, so one shops compensation will not be the same for another shop. Each will have different results. Some far more drastic than another.

SPECIAL NOTE:
Once you do get a handle on your dot gain aka tonal curve adjustments, (use that on current or future orders only). Re-orders with halftone work (with a new tonal curve adjustment) can be drastically different then previously printed. Therefore, it's vital that you use the new compensation only on newly separated jobs.



« Last Edit: December 30, 2014, 01:40:41 PM by Dottonedan »
Artist & Sim Process separator, Co owner of The Shirt Board, Past M&R Digital tech installer for I-Image machines. Over 28 yrs in the apparel industry. Apparel sales, http://www.designsbydottone.com  e-mail art@designsbydottone.com 615-821-7850


Offline ScreenPrinter123

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Re: Free downloadable halftone test file
« Reply #1 on: December 10, 2014, 07:46:36 AM »
Thanks Dan, this is some good stuff!

Offline StinkyDaddy

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Re: Free downloadable halftone test file
« Reply #2 on: December 14, 2014, 08:44:22 PM »
Thanks Dan.

Offline StinkyDaddy

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Re: Free downloadable halftone test file
« Reply #3 on: December 19, 2014, 12:40:30 PM »
I've been playing around with this when I've had some free time.
The Wilfex EasyArt PS plugin has been my method for my halftone output.
Normally I would layer and mask the EasyArt file and the original to get good text and halftones, I didn't on this one and you can see that in the text and lines.
This got me motivated to streamline my process a little and I loaded GhostScript and did a bit of reading on how to use it.
I'm happier with the GS film from AI and now that I sort of have GS figured out it should save me some time.

I do see that I am not holding detail on both ends of the grey scale, any other observations and suggestions?

Thanks

Offline Dottonedan

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Re: Free downloadable halftone test file
« Reply #4 on: December 19, 2014, 01:56:00 PM »
Thanks for posting the print results. If you want some good feedback, you can try to set your camera on a higher setting of resolutions and try and take some more tighter, more focused shots at high rez. I opened these in Photoshop but it's grainy and I can't see really what you are holding in the shadows and highlights. You can also scan the printed shirt. That might help as well. 


Do either of these Rip options enable you to make adjustments for dot gain?


You're holding some line work in the .25 line area so thats real good.


« Last Edit: December 19, 2014, 02:01:18 PM by Dottonedan »
Artist & Sim Process separator, Co owner of The Shirt Board, Past M&R Digital tech installer for I-Image machines. Over 28 yrs in the apparel industry. Apparel sales, http://www.designsbydottone.com  e-mail art@designsbydottone.com 615-821-7850

Offline StinkyDaddy

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Re: Free downloadable halftone test file
« Reply #5 on: December 19, 2014, 02:18:10 PM »
This is a close up of the GS 45 lpi on 230. This was the second print, done with a 70/90/70, one push stroke.

Offline Dottonedan

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Re: Free downloadable halftone test file
« Reply #6 on: December 19, 2014, 02:34:02 PM »
Your 95% looks like it is holding some negative dot information (in print) so that would be good.  I can't tell for sure really, with the coverage having some of the shirt pop up thru.


Below 10%, your losing something and this could be either from over exposure, ink or maybe your printer device is not actually putting the dots onto the film (as heavily) as it should or maybe it physically can't based on your machines settings. It could be partly both the printer and exposure and even ink.


How does your films look?  Can you see good dots all to way down to 3% on film? If so, then it's your exposure.
Sometimes thinning the ink down more, can help you gain a few more dot %'s in print so that it can flow tru those tiny holes easier.



Artist & Sim Process separator, Co owner of The Shirt Board, Past M&R Digital tech installer for I-Image machines. Over 28 yrs in the apparel industry. Apparel sales, http://www.designsbydottone.com  e-mail art@designsbydottone.com 615-821-7850

Offline StinkyDaddy

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Re: Free downloadable halftone test file
« Reply #7 on: December 19, 2014, 06:24:37 PM »
Here's the film.

The 95%'s looked good on the screen.
I could see some dots on the screen below 10, but they lost consistency below 10. Something like maybe 1/3 of the dots showing up at 5%.
You mentioned thinning the ink. This was printed first thing this morning, before I got the shop good and warm. The ink was still a little stiff.
I think I'll dial the exposure back a little on the next try.
As for dot gain, I haven't found any settings for that in GS. I'm not sure if there is anything in AI.

Thanks again.

Offline StinkyDaddy

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Re: Free downloadable halftone test file
« Reply #8 on: December 22, 2014, 10:30:43 AM »
I cut my exposure time from 45 seconds to 40 this morning using the same film as last time.
The reduced exposure seems to have made a difference.
One pic is of the screen held up to a shoplight right before I put it on the press.

Thanks again.

Offline Itsa Little CrOoked

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Re: Free downloadable halftone test file
« Reply #9 on: December 22, 2014, 11:40:22 AM »
Hey Dan,

When you get a minute, could you re-save that file as a CS-2 version or lower for Illy and maybe PM me with it?

I'm too tight to upgrade, I guess. I can print it from Photoshop now, but I'm not confident of the tiny details.

Thanks! And MERRY CHRISTMAS to you and yours!

Stan

Offline Dottonedan

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Re: Free downloadable halftone test file
« Reply #10 on: December 22, 2014, 03:07:22 PM »
Hey Dan,

When you get a minute, could you re-save that file as a CS-2 version or lower for Illy and maybe PM me with it?

I'm too tight to upgrade, I guess. I can print it from Photoshop now, but I'm not confident of the tiny details.

Thanks! And MERRY CHRISTMAS to you and yours!

Stan




Will do.  I thought I saved it back pretty far, but must not have been far enough. Last night I started working on my test for multi colors of 1% up to 100%  (blending from one stock color to the next) so that you can obtain good print colors to use as a gauge for what % you need with what color to obtain a specific target color (using your own stock colors or specific pms colors. Both on darks and lights.  It's a pretty valuable tool to have but it's a bit time consuming. I'm half way done with that (I think).
Artist & Sim Process separator, Co owner of The Shirt Board, Past M&R Digital tech installer for I-Image machines. Over 28 yrs in the apparel industry. Apparel sales, http://www.designsbydottone.com  e-mail art@designsbydottone.com 615-821-7850

Offline Dottonedan

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Re: Free downloadable halftone test file
« Reply #11 on: December 22, 2014, 03:16:41 PM »
I cut my exposure time from 45 seconds to 40 this morning using the same film as last time.
The reduced exposure seems to have made a difference.
One pic is of the screen held up to a shoplight right before I put it on the press.


Thanks again.




Those look better.  It sure looks like you're holding with your ink, everything you are providing. I would say to cut the time back a tad even more. You want to hold the dots (see them) in the screen, even tho you may not hold them on press due to the mesh blocking the ink on the 3% and lower, but of the 3% and above, you should more (more consistently). I see a good many dots missing from the 3,4 and even 5. But that's still good.  Check your films (in that 3% range) and make sure your printer device is actually kicking out those dots onto film.   Good pics!


EDIT:  Even your 7%'s seem to be missing some in a few areas. Looks good tho, like it should produce a pretty good gradation. Just missing some dots. After comparing to your original pic, I think it's in your film printer that is causing some of that. It seems consistent like maybe some nozzles can be clogged. Do some nozzle checks and auto cleans.
« Last Edit: December 22, 2014, 03:21:22 PM by Dottonedan »
Artist & Sim Process separator, Co owner of The Shirt Board, Past M&R Digital tech installer for I-Image machines. Over 28 yrs in the apparel industry. Apparel sales, http://www.designsbydottone.com  e-mail art@designsbydottone.com 615-821-7850