QTR-Quadtone RIP

Hi,

I'm hoping someone can help me, i'm kind of new to this and i'm attempting to create a profile for making digital negatives with Pictorico OHP on my stock Epson 1400. 

The problem i'm having is that all my test prints from the negatives thus far have been very light (which is to say, the negatives are too dark), too light yet to begin linearizing. I keep cranking the Gray_Shadow and Gray_Highlight up, and the Default_Ink_Limit down, but it seems wrong. the current working values are as follows: Default_Ink_Limit=14, Gray_highlight=10, Gray_Shadow=14, Gray_Gamma=1.2. This seems somewhat more extreame than it should be, based on other profiles i've seem. I am copying the K curve to CMY.

I'm guessing i'm probably making some kind of silly newby error, but can't think where...

-Ted

I'm about to be exploring digital negatives on Pictorico for a certain alt process, so your situation anticipates where I'm likely to be in a short while.

All I can do is share some general links that might eventually be helpful to ME ;-).  I am NOT speaking from experience.

Ron Reeder is making INQUIRIES it seems with Epsons 2200 and 4000 ...
http://www.digital-negatives.com/index_quadtone.htm
http://www.ronreeder.com/page8117.html

You may know of Dan Burkholder, who is an authority (who does <a href="http://www.danburkholder.com/Pages/right_frame_pages/workshop_2-06/Workshops.html">workshops</a>) with Platinum Palladium and a variety of digital processes ...
http://www.danburkholder.com/

See if you can find someone working in your specific process (contact or enlarger printing on ___ ?) who might share a known-good curve and maybe adapt it to the 1400.

Sorry I can't be more specific.


--- In QuadtoneRIP@yahoogroups.com, "mysteriousmirage" <mysteriousmirage@...> wrote:

>
> Hi,
> 
> I'm hoping someone can help me, i'm kind of new to this and i'm attempting to create a profile for making digital negatives with Pictorico OHP on my stock Epson 1400. 
> 
> The problem i'm having is that all my test prints from the negatives thus far have been very light (which is to say, the negatives are too dark), too light yet to begin linearizing. I keep cranking the Gray_Shadow and Gray_Highlight up, and the Default_Ink_Limit down, but it seems wrong. the current working values are as follows: Default_Ink_Limit=14, Gray_highlight=10, Gray_Shadow=14, Gray_Gamma=1.2. This seems somewhat more extreame than it should be, based on other profiles i've seem. I am copying the K curve to CMY.
> 
> I'm guessing i'm probably making some kind of silly newby error, but can't think where...
> 
> -Ted
>

--- In QuadtoneRIP@yahoogroups.com, "mysteriousmirage" <mysteriousmirage@...> wrote:
>
> Hi,
> 
> I'm hoping someone can help me, i'm kind of new to this and i'm attempting to create a profile for making digital negatives with Pictorico OHP on my stock Epson 1400. 
> 
> The problem i'm having is that all my test prints from the negatives thus far have been very light (which is to say, the negatives are too dark), too light yet to begin linearizing. I keep cranking the Gray_Shadow and Gray_Highlight up, and the Default_Ink_Limit down, but it seems wrong. the current working values are as follows: Default_Ink_Limit=14, Gray_highlight=10, Gray_Shadow=14, Gray_Gamma=1.2. This seems somewhat more extreame than it should be, based on other profiles i've seem. I am copying the K curve to CMY.
> 
> I'm guessing i'm probably making some kind of silly newby error, but can't think where...
> 
> -Ted


Here's where I think your error is: Exposure time. Your print turns black where there's no ink on the negative, so adjusting your ink limits won't make a bit of difference.

When doing a process calibration like this, the first thing you have to do is determine your exposure time to get a good max black through clear Pictorico (and a mylar layer, etc. if you use that to separate your negative from the print).

Once you have your exposure time worked out for a given paper/sensitizer/etc. combination, then you need to start worrying about QTR. First nail down your ink limit for whatever combination of ink colors you're using (and you probably don't need to use any magenta ink...it doesn't really block any UV). I always do this with gamma=1, highlight and shadow=0, to start. Always keep your exposure time the same, and adjust ink limits up (more ink) if your 100% black step is not paper-white, or down (less ink) if anything less than your 100% ink step is paper-white.

Once you get to this point, then you can start worrying about curve shape and linearization.

Hope this helps.

--Greg

You may wish to vist DPUG.ORG where you can find lengthy discussions and a dedicated forum for making digital negatives with QTR and other methods. Ron Reeder posts there and you can find starter curve files. Plus it's a begginer friendly environment for people wishing to get involved.

Greg is a frequent poster there and has given you some succint advice.

Good luck,

Don Bryant
> > I'm hoping someone can help me, i'm kind of new to this and i'm attempting to create a profile for making digital negatives with Pictorico OHP on my stock Epson 1400. 
> >