Is gloss differential on custom profiling targets OK?

qtr
curves
piezography

#1

I printed targets to send for custom curves on Photo Rag Baryta. I dried the target for 5 minutes before printing the 30000GO pass. I noticed that the targets have gloss differential in the darkest 10 patches of the DTP target.

Then I printed another target, let it sit 48 hours, then did 5 minutes with the hair dryer. There’s still gloss differential in the darkest 10 patches of the target.

Will the custom curve reduce the amount of black ink in these patches and eliminate the gloss differential? Or do the targets need to have more GO passes before measuring?

Using Epson 7800 set up with a Piezo2 WN-SEL inkset, warm neutral opaque black as shade 1, the most recent P2 master gloss curve, QTR 2.7.5, Print-Tool 10.1.0, Mt. Lion 10.8.5, Hahnemuhle Photo Rag Baryta paper.


#2

You could bump to 35000 units for the Photo Rag Baryta. You would want a custom to be reflective of the print you intend to make with it. So try 35000 first. Then 40000. Too much is just as bad as too little. You just want the bronzing and differential gone.


#3

Thanks Jon, I will try that.

I’m curious abut the P2 curves you supply for download. (I am looking in the curves folder for x800/x880 printers using Warm Neutral inkset). When you created those curves, did you find that they all responded well to 30000 units of GO? Or did you find some needed more GO than others?

When I look at the amounts of ink used in CurveView, I see the p2 master curve has a higher maximum (34) in the Y channel (where my shade 1 is) than the Y curves for most of the baryta surface papers, like Photo Rag Baryta, FineArt Baryta, Exhibition Fiber, Canson Baryta. Curves for those papers are around 12 in the Y channel.

The Y channel values on Type 5, Photo Rag Pearl, seem closer to the master curve, and I haven’t had the gloss differential in the blacks happen as much (or at all) on Type 5 or Photo Rag Pearl.


#4

Type 5 is designed for Piezography although it works great with color inks. So its GO load is very light at 30000 units.
Hahnemuhle is better with 35000 units.
Some of the papers are so bronzy such as the Ilford and Canson. They require often 40000.

If a paper curve is closer to the Master Curve, it is more ideal to the surface we expected when we made the master curve.

You need to choose a paper that prints well, does not bronze so much that you have to GO it so much in order to battle its characteristics.
Personally, I think that Type 5 is the best baryta around. It’s surface is convincing and it takes a great ink load.
Second favorite is Epson Exhibition Fiber which is a very optically bright white paper that reminds me of typical Ilford silver paper.


#5

[QUOTE=jon;6796]Type 5 is designed for Piezography although it works great with color inks. So its GO load is very light at 30000 units.
Hahnemuhle is better with 35000 units.
Some of the papers are so bronzy such as the Ilford and Canson. They require often 40000.[/QUOTE]

It would be useful to see these numbers listed somewhere. I’d not seen them before. I’d only seen a “suck it and see” recommendation.

I use mainly Ilford and I’m inclined to agree that 30,000 isn’t enough. But I’ve been a little reluctant to use more because on a cartridge-on-the-print-head printer each refill of the GO cart triggers a head clean. It’s amazing how fast the GO cart goes down.

I’ll give it a try, but for 40,000 units on IGFS, do you find that it works well enough in 1-pass or is a 2-pass application needed?


#6

Type 5 is ours and its coating remains the same and it just always needs only 30000.

Canson Baryta was very regular and could be used with 30000, but we noted some changes to it about 2 years ago and then again a year ago, and the 40000 is minimal. In our studio we do not like using it but some customers require it and we charge for two double coatings of 30000. It’s sometimes the only way to get rid of all the bronzing with the batches of it that are in our studio.

HPR papers go up and down. usually 35000 works.

Epson EEF also remains steady and usually just the 30000. Every so often we get a batch that needs 35000.

IGFS usually requires only one pass of about 40000.

So - we do not want to set the other papers in stone because too much GO will soften detail…we just really know our paper and how it is coated and that the coating does not change. The others are for whatever reason, subject to changes.

You want just enough!


GO using HDPK settings
#7

Thanks. That’s helpful. I hear you that you’re wary about giving hard and fast GO rules, especially when there’s variation in coatings. But I still think that what you’ve said in this thread should be given more prominence somewhere on IJM or the blogs as indicative guidance for commonly used papers.

I find that it’s not economic to ship paper to the other side of the planet. The weight makes the freight expensive. It’s bad enough locally. And 13"x19" only makes matters worse. Plus you only sell US sizes I assume, so you don’t sell A4 or A3? So we’re stuck with what we can buy locally. I’d consider trying some of yours if I could find a way around these problems.

p.s. Have you noticed any changes in IGFS with the change in ownership and the recommenced production? Perhaps it’s too early to say as you haven’t bought any new stock. All mine is still pre-bankruptcy, i.e. from 2013.