Kodak Sonora XP – light sensivity

cementary

Well-known member
We're thinking on switching to sonora xp plates. The main question for now is the light sensivity of these plates (second is press stability with them)
For now (with capricorn gt) we store imaged plates vertically image-to-image side with paper between them – so no light enters inside.

Will this way of storing imaged plates work for sonora xp?

We won't be able to image right-before-print 'cause we've got plenty of printing machines (5 plate formats).
 
You should be fine that way. You might get a little light leak around the very edges of the plates, but unless you are imaging all the way to the edge it's not a problem. We've been using the Sonora for almost a year and in general we image plates a day ahead of time, but on long weekends have imaged plates 4 or 5 days ahead with no problems.

The only real problem we've had with light sensitivity was from the Achieve platesetter - it has an autoloader and the plate bay is not light-tight and the machine is not in a dark room, so if we didn't image any plates for a day or so the very first plate we ran would be unusable. We temporarily solved this by putting a dummy plate over the stack (we used an actual plate and wrote on it with a Sharpie so that if a pressman had to run a replacement plate overnight he would know to just run it again to get a good plate. If we used anything else to block the light we were afraid it would jam the machine).

Recently, Kodak came up with a retro-fit kit that blocks most of the light, so we don't need to use the blocking plate anymore.
 
The only real problem we've had with light sensitivity was from the Achieve platesetter
That's greate new, thank you!
We've got 2 magnus vlf with cassette loaders and it's quite dark inside.
So you're expirienced sonora user – could you tell how you QC these plates? Do you wash digital stripe with fount solution or with smth else?
And how your pressmen understand which plate for which separation?
 
There's enough contrast that you can see the image to identify each plate. If you can't see the slug, chances are the plate was exposed to light for too long.

We don't do any QC on the plate (other than visually spot checking for content) - we've never had our CTP drift, and since there's no chemistry to monitor everything is rock solid.
 
We just switched to the Sonora XP plates. We ended up getting a new/used Screen CTP because our Presstek was just to unstable. You should be able to see the image on the plate to check what colour it is, if you cannot it is probably not being imaged correctly and will ware quickly on the press.

We are usually a day ahead when imaging plates, I put them face to face with a sheet between the plates and then put them in a large sleeve we made from old boxes. Have not had an issue yet doing this.
 
We don't do any QC on the plate (other than visually spot checking for content) - we've never had our CTP drift, and since there's no chemistry to monitor everything is rock solid.
But what about applying print curve (calibration curve)? How do you measure patches on plate before print run (to be sure that curve was properly applied)?

One more question – what about press behavior with this plates? Especially if plates develops on-press how often (in compare with conventional plates) do you change fountain solution on press?
 
I'll answer my own question – it turned out that plate coating is removed with ink transfer on substrate within first 10 sheets. I'm really embarrased that i didn't even think about that way of removing coating. So the goal is not to pre-damp plate too much but to operate press quite same way
 
But what about applying print curve (calibration curve)? How do you measure patches on plate before print run (to be sure that curve was properly applied)?

We don't measure patches on the plate (other than during initial setup when the machine was installed, or if we were to change plate vendors), nor has any shop I've ever worked at. For one thing, we only run one curve, and secondly, we have the curve name printed automatically in the slug info on each plate. If an occasion arises where I have to apply a different curve, that info tells me which curve was applied.
 

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