AGFA AccuSet 1000 density issue

VladCanada

Well-known member
It looks for me you have some sort of Laser Driver Module problem. You told us first job/plate looks good. May be after warming up of Accuset you have incorrect laser modulation. Please check coaxial RF cable connectors for good contact
 

tsinger

Member
I just finished processing test page 1 and test page 2 directly from the Accuset. Any idea what values I should be looking for?
 

VladCanada

Well-known member
First of all find a line with +D around 3.6-3.8. Accuset was unable to get 4.0 Then check 50% how far you are
 

ssutton503

Active member
The use of the word "density" is bothering. The only time you need to read the density of the film would be to make sure you are getting the exposure/development you need. You should image a film, read a solid black area and make sure your density is what you expect it to be. It has been a while since I used film but 3.6 to 3.8 seems about right. Once you have you solid density correct (and yes, density of the film is dependent on the exposure and the processing) then you would switch the densitometer "Dot" mode to read your screen percentages. If my density was correct but my percent dot was off (what I expect to be a 50% dot is really a 55% dot) I would adjust my calibration curve(s). Again, it has been a while since I worked with film but I can't remember a reason to be measuring the density of a screened area. Unless all I had was a densitometer capable of reading only densities and I was trying to convert a density number to a percent dot.
 

tsinger

Member
Yeah I believe my terminology was wrong. The density of the solid black parts of my negatives are reading at 5.16, and when I check the solid clear areas (areas that should have 100 percent dot), it is reading 70 percent. I have been on the phone with several people today, and it seems that my exposure might have been too high. I was running jobs through the image setter at 255 exposure but bumped it down to 195 in accordance with some of the other page setups that were previously stored in the RIP. This helped bring my dot percentage up to the 85-88 range, but I'm still having trouble getting that number to 100. Density is now reading at 3.68. Any suggestions?
 

VladCanada

Well-known member
Let's talk about positive image exposure and you will understand a principle of Accuset internal test file.
255 is MAXIMUM exposure level of Accuset and never been used in normal circumstances.
 

tsinger

Member
That's what I just read actually when going through the manual! So 195 seems more ideal then, correct? Will I be sacrificing my dense areas if I take my exposure even lower in order to gain more dot percentage? Is this something I can compensate with an ideal mix of chemistry?
 

VladCanada

Well-known member
Please DO NOT sacrifice optical density in favor of Dot percentage. Use Calibrating SW instead and keep 3.6-3.8 D at solid area
 

SteveSuffRIT

Active member
The X-Rite 361-T is an oldie but goodie, transmission densitometer.
It can read density, dot area, both negative and positive.
Zero on clear area film area (base & fog).
A transmission density of 0.30 will convert into a 50% dot.
The dot is more important than the maximum density (Dmax).
Typical offset litho negative plate exposure with Stouffer step scale T2115 (21 steps, each 0.15 density) recommends a solid#6, gray #7, clear #8. So, a Dmax >1.2 is sufficient (in theory), which is why inkjet or laser toner films can be used (in practice) instead of photographic films for platemaking.
Steve Suffoletto
 

tsinger

Member
Thanks for the info, all. I’ve been doing immense research on this lately , and I think a lot of this is really starting to click for me. It looks like I need to zero in on finding the proper exposure and then calibrate the Harlequin rip to the dot % readings from a calibration test. Correct?
 

Color Optimized?

Ink
by Noel Ward, Editor@Large
Color is in demand in all types of documents, making color management a critical part of Digital Printing 5.0. Managing color on one device/press can be an easy task with the correct tools and processes. But managing color to ensure printed pages are consistent and repeatable across the different substrates and color gamuts of toner and inkjet can be a much bigger challenge. Properly implemented color management workflows can help achieve consistent color results across multiple devices. Although many end-customers are claiming satisfaction with “pleasing color,” two challenges are still in play. Link to Article

 
Top