Prinergy problem with ONE Bit Tiff

[Bojan_Libra]

Hello, I have problem with gradient with Prinergy EVO 4.1, when I use Harlequin 8 I don't have problem but I need to use Prinergy EVO from other reasons. To see problem please download this test files from Prinergy EVO and Harlequin.
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I use 1500 dpi with Basys 850 CTP

Thank you

[james.bredenhof]

Hi Bojan,

I was intrigued, so took a look at the file.
The original PDF doesn't use a vector radial shading object, but simply an 8-bit bitmap (i.e. limited to 256 shades).
If you apply a curve to the image in Photoshop, you can see similar effects. See attached.

Why doesn't Harlequin appear to have the problem? My guess is that it probably would; in Photoshop, the banding effect varies depending on the curve you apply to it, so perhaps the Harlequin curve is slightly different than the Prinergy curve.

If the file was created with a vector radial shading object, the quality would have been much better, both with and without the curve applied to it.

2 cents.
James

[Bojan_Libra]

I have CTP Studio and I dont made that files, I just expose on plate, I also have Creo Trendsetter 800 II Quantum and on that ctp I dont use calibration of plate because percent of screen is good (that is best ctp ever made) and also use Prinergy Evo 3.1 but directly without One Bit Tiff and I never have such problem. I think that Prinergy 4.1 doing something wrong with making one bit tiffs.
All vector gradient at the end become bitmaps with 300 or 1500 dpi (in my case).
Maybe only different is that Harlequin have "Generate extra gray levels /4096" that option Prinergy Evo dont have.
I wish that someone who also use Prinergy Evo try to make One Bit Tiff to see what will we get. (It is important to be 1500 resolution and that use calibration of plate), files is on rapidshare