QTR-Quadtone RIP

I am trying to define a profile for making a positive for photopolymer gravure for use without a aquatint screen.

the main  problems are how to make and use the stochastic patron and with what ink combinations? or is Black Ink only printed with 720 dpi as used on simple printers the solution?

remko

Remko,

I recently attended a workshop using a photopolymer sheet for photogravure work.

The understanding I have from the tutor is that you do 2 separate exposures, one first with the screen then with the positive.  One controls the highlight end of the gravure, the other controls the shadow region, but that both are necessary to get a full tonal range on the print.  

I have only had one chance since then to try it at home, but need to work out the exposures under the UV lamp.  My initial attempt was grossly underexposed, little etching achieved.

Am doing the trials with a 21 step wedge, so I can measure the tonal ranges (when I get that far) and apply a correction curve to linearise it.

I use an Epson Stylus Photo R2880 printer, with Agfacopy sheets and the PK ink.

Hope this is of some help with your query.

Regards,

Jim Thyer

  ----- Original Message ----- 
  From: remko@... 
  To: QuadtoneRIP@yahoogroups.com 
  Sent: Friday, August 05, 2011 11:06 PM
  Subject: [QuadtoneRIP] QTR profile for polymere gravure on AGFA select/copy jet with Epson 3800


    
  I am trying to define a profile for making a positive for photopolymer gravure for use without a aquatint screen.

  the main problems are how to make and use the stochastic patron and with what ink combinations? or is Black Ink only printed with 720 dpi as used on simple printers the solution?

  remko



  

[Non-text portions of this message have been removed]

Jon Cone is attempting the same thing with piezography inks and QTR. Read his blog for a description. I don't think he has it worked out yet but is trying to do it without the aquatint screen by experimenting with dithering patterns.


On Aug 5, 2011, at 9:06 AM, remko@... wrote:

> I am trying to define a profile for making a positive for photopolymer gravure for use without a aquatint screen.
> 
> the main problems are how to make and use the stochastic patron and with what ink combinations? or is Black Ink only printed with 720 dpi as used on simple printers the solution?
> 
> remko
> 
> 



[Non-text portions of this message have been removed]

Hello Remko,

If you really want to make an digital negative/positive for photopolymer without an aquatint screen you don't use the full advantage of a photopolymer. 

When you print it in 1 film, with an stochastic screen (or anything else), you get a flat 1-0 surface on your polymerplate. Corresponds well with the normal screenings on offset and normal printing techniques.

But if you want to: i set the 100% K in my file to 80% K, and the other grays follow as well.
A screening of 300 lpi @ 45°. And set it to bitmap at 1200 dpi.

What kind of photopolymer do you use?

When you use the aquatint screen, you can use the 100% K files. Because the aquatint 'breaks' the 100% areas where you normally get the burning out spots.

@Jim:
The 21 step is only good for determinating the max exposure. When you know that time, al the rest has to be calculated with the ChartThrob script in photoshop.

I personal use the Perfect Proof HD Films, Epson 3800, and UC inks for negatives.

Best
Stijn Heirbaut
www.fragile-surface.eu


--- In QuadtoneRIP@yahoogroups.com, "Jim Thyer" <jimth@...> wrote:

>
> Remko,
> 
> I recently attended a workshop using a photopolymer sheet for photogravure work.
> 
> The understanding I have from the tutor is that you do 2 separate exposures, one first with the screen then with the positive.  One controls the highlight end of the gravure, the other controls the shadow region, but that both are necessary to get a full tonal range on the print.  
> 
> I have only had one chance since then to try it at home, but need to work out the exposures under the UV lamp.  My initial attempt was grossly underexposed, little etching achieved.
> 
> Am doing the trials with a 21 step wedge, so I can measure the tonal ranges (when I get that far) and apply a correction curve to linearise it.
> 
> I use an Epson Stylus Photo R2880 printer, with Agfacopy sheets and the PK ink.
> 
> Hope this is of some help with your query.
> 
> Regards,
> 
> Jim Thyer
> 
> 
>   ----- Original Message ----- 
>   From: remko@... 
>   To: QuadtoneRIP@yahoogroups.com 
>   Sent: Friday, August 05, 2011 11:06 PM
>   Subject: [QuadtoneRIP] QTR profile for polymere gravure on AGFA select/copy jet with Epson 3800
> 
> 
>     
>   I am trying to define a profile for making a positive for photopolymer gravure for use without a aquatint screen.
> 
>   the main problems are how to make and use the stochastic patron and with what ink combinations? or is Black Ink only printed with 720 dpi as used on simple printers the solution?
> 
>   remko
> 
> 
> 
>   
> 
> [Non-text portions of this message have been removed]
>

Hello Remko,

If you really want to make an digital negative/positive for photopolymer without an aquatint screen you don't use the full advantage of a photopolymer. 

When you print it in 1 film, with an stochastic screen (or anything else), you get a flat 1-0 surface on your polymerplate. Corresponds well with the normal screenings on offset and normal printing techniques.

But if you want to: i set the 100% K in my file to 80% K, and the other grays follow as well.
A screening of 300 lpi @ 45°. And set it to bitmap at 1200 dpi.

What kind of photopolymer do you use?

When you use the aquatint screen, you can use the 100% K files. Because the aquatint 'breaks' the 100% areas where you normally get the burning out spots.

@Jim:
The 21 step is only good for determinating the max exposure. When you know that time, al the rest has to be calculated with the ChartThrob script in photoshop.

I personal use the Perfect Proof HD Films, Epson 3800, and UC inks for negatives.

Best
Stijn Heirbaut
www.fragile-surface.eu


--- In QuadtoneRIP@yahoogroups.com, "Jim Thyer" <jimth@...> wrote:

>
> Remko,
> 
> I recently attended a workshop using a photopolymer sheet for photogravure work.
> 
> The understanding I have from the tutor is that you do 2 separate exposures, one first with the screen then with the positive.  One controls the highlight end of the gravure, the other controls the shadow region, but that both are necessary to get a full tonal range on the print.  
> 
> I have only had one chance since then to try it at home, but need to work out the exposures under the UV lamp.  My initial attempt was grossly underexposed, little etching achieved.
> 
> Am doing the trials with a 21 step wedge, so I can measure the tonal ranges (when I get that far) and apply a correction curve to linearise it.
> 
> I use an Epson Stylus Photo R2880 printer, with Agfacopy sheets and the PK ink.
> 
> Hope this is of some help with your query.
> 
> Regards,
> 
> Jim Thyer
> 
> 
>   ----- Original Message ----- 
>   From: remko@... 
>   To: QuadtoneRIP@yahoogroups.com 
>   Sent: Friday, August 05, 2011 11:06 PM
>   Subject: [QuadtoneRIP] QTR profile for polymere gravure on AGFA select/copy jet with Epson 3800
> 
> 
>     
>   I am trying to define a profile for making a positive for photopolymer gravure for use without a aquatint screen.
> 
>   the main problems are how to make and use the stochastic patron and with what ink combinations? or is Black Ink only printed with 720 dpi as used on simple printers the solution?
> 
>   remko
> 
> 
> 
>   
> 
> [Non-text portions of this message have been removed]
>