Accurip FM dot

[endhymns]

So, I'm looking to do a bit of experimenting with stochastic dots outputted from Accurip to accommodate some illustrations being printed in the not too distant future. I'm running an Epson T3270 with Accurip Black Pearl and currently have my resolution settings at 720x720 as per Accurip's suggestion of using a square dot resolution. When printing a test file out of Illustrator at 250 microns, dots look good from 5%-90% with things getting pretty murky in the 95% range. However, if I output a gradient as opposed to test squares in 5% increments, I get some weird banding issues in the upper ranges (maybe 80% up). From my limited experimentation, this can be controlled with the gamma settings if I'm not mistaken, but without simply using trial and error and burning film, is there a way to know where I should be sitting ballpark with these settings?

And on the same note, I'm open to other alternatives for achieving dithered dots. I've had more consistent results when using a diffusion dither bitmap in Photoshop, but am looking to avoid bitmapping in Photoshop if possible for workflow reasons.

Thanks in advance!

[blue moon]

So, I'm looking to do a bit of experimenting with stochastic dots outputted from Accurip to accommodate some illustrations being printed in the not too distant future. I'm running an Epson T3270 with Accurip Black Pearl and currently have my resolution settings at 720x720 as per Accurip's suggestion of using a square dot resolution. When printing a test file out of Illustrator at 250 microns, dots look good from 5%-90% with things getting pretty murky in the 95% range. However, if I output a gradient as opposed to test squares in 5% increments, I get some weird banding issues in the upper ranges (maybe 80% up). From my limited experimentation, this can be controlled with the gamma settings if I'm not mistaken, but without simply using trial and error and burning film, is there a way to know where I should be sitting ballpark with these settings?

And on the same note, I'm open to other alternatives for achieving dithered dots. I've had more consistent results when using a diffusion dither bitmap in Photoshop, but am looking to avoid bitmapping in Photoshop if possible for workflow reasons.

Thanks in advance!

One of the main reasons I like FlimMaker better than AR is because of the banding issues you described. They were pretty subtle, but visible. My thinking was it was the AR engine related, but would love to hear if there is actually a setting that would control/correct this issue.

Any FM work we did was always done through Photoshop. There really wasn't a lot of it so going about it the long way was not the issue. Are you anticipating a larger volume of work that would require it?
Also, what dpi are you outputing your films? Maybe an adjustment there might help.

pierre

[Dottonedan]

I played with AR at 720x720 and printed one film repeatedly moving the art a few inches and outputting again so I'd have the various changes all on one film.  200,150,100 micron. All filled in at my 90% to 99. (That should not happen). So what we do here, (in order to take advantage of the smaller dots in a 75-100 micron, is t open up your shadow tones at the point where it fills in. What it's doing, is spacing them further apart, restricting them from filling in too easily. You just have to find that micron size and go with it.


The 1-10% printed fine, but like you said, there is a funk at the 1% area. That area is typical of FM. There are better RIPS that handle that area better, (higher algorithms than Photoshop can put out) but are far to expensive to make it feasible. Like 10k expensive. One is called Crystal raster from Agfa. They are more for wet film imagesetting.


Apparently for the shadow tones, maybe it's the limitations of inkjet. Go too small and it's just going to fill in. I have seen it happen on the first gen of Gerer DTS back in early 1996-97 but more extreme.  The wet wax (back then), would just blob and run together as you got to far into the shadow tones so a 35lpi would fill in solid at the 65% tone.


I will say tho, I've found that while we are told 1440x1440 puts down more ink than 720x720....it does it slower...thus, more accurately. Better shadow tones, so look at that. Maybe change up your ink droplets to compensate if you start to get too much too fast.


Pierre and I did what I would figure to be in the area of a 75 micron (when I compare to what I'm seeing on my films). I'm guessing. But we did twice as small from what I'm getting of of our 100 micron. Thats pretty small. In Photoshop bitmap rez, that would be 260 rez if I'm not mistaken and I was surprised to see that P could hold that but he did and did it GREAT.




I don't understand how gamma plays a role in the output yet, but I haven't tested that part. Gamma (to me thus far), usually pertains to color (highlights and shadows and grey tones on the monitor.