# Alternatives to Accurip for Halftones



## SuperluxeFibers (Nov 4, 2010)

Hi,

What are some other alternatives to Accurip when converting a .jpeg to print in halftones? 

The Photoshop filter isn't a very accurate alternative.

Does anyone have any saved actions in PS that can simulate Accurip's halftone production?

In Photoshop I have seen the channels separated, then converted to grayscale, then to bitmap, but I don't have a good read on what to input in the dialog boxes to mimic what Accurip is doing.

I know there are some creative folks out there and surely someone has a solid way to tackle this.

Any help would be appreciated,
Jon


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## tpitman (Jul 30, 2007)

Quality of dot edge using the grayscale to bitmap halftone trick in Photoshop depends a lot on the resolution of the graphic to begin with. A bitmap halftone dot will have a finer edge to it if the original file resolution was 600 dpi as opposed to 150 dpi. For those of us who remember the difference in a 300 dpi laser printer and a 600 dpi laser printer when they first cam out, you'll know what I mean.
In the dialog box you get when you choose "halftone" when converting to bitmap, try 300 dpi as your output, and pick a screen frequency and angle to match what AccuRip was outputting, such as 55 lpi at a 22.5 angle. Dot shape should be either elliptical or round. Most use elliptical for screenprinting.
Print your film and look at it through a loupe on a light table, and compare it to film output to the same frequency through AccuRip. If possible, output an old file that you'd done using AccuRip so the comparison in quality is easier to see.


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## RespecttheCraft (Feb 19, 2010)

ive always found photoshop to be accurate. like tpitman said always start with a hi res image. when you go into photoshop and convert to bitmap have the output resolution over 300dpi. ideally you should set this at the resolution you are going to be printing your positives at. it helps stave off moire and delivers a much higher level of detail. 1440 is kind of high for me - i usually do 720, but every printer is different. if that doesnt help, play with using higher lpi counts. if that doesnt work.... buy a rip lol. theyre a step up from photoshop. its all about the algorithms the program uses to place the dots


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## tpitman (Jul 30, 2007)

When I'm setting up a job from scratch, I'll use 600 dpi if I can, otherwise, 300.
The only other thing you lose by doing the grayscale/bitmap halftone method is any postscript accommodation for dot gain. 50% will come out as 50%. An alternative is to print your seps as a .ps file and open that in Ghostscript/Ghostview. Depending on the job, and especially if I have trapping built in, I'll do it that way. Simple jobs, process color, and simulated process get the grayscale/bitmap halftone treatment. You can record actions so that you click on the grayscale file and run the action and it'll go through the whole routine. You do have to record a separate action for any differences, such as different screen frequencies, but if all you do is 55 line screens at 22.5 degrees with a round dot, that's all you need.


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