Digital BW, The Print

First of all, a happy 2007 to you all! I hope in this year the world 
will not be as black and white as our pictures ;-)


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Greg" 
<dfaprinting@...> wrote:

> Do you
> have something that is fairly stable like a Macbeth chart that you can
> measure? That way you can check for consistency between sessions.

The same thought occurred to me. I did checks with both the GMcB 
Digital Color Checker SG (a semi-matte plastic camera target) and the 
GMcB Eye-one Scan Target 1.4 (a glossy paper target). 

There seems to be nothing electronically wrong with my Eye-one. With 
the glossy scan target the measurements were immediately very 
reproducible (noise of L* = 0.1/0.3). With the semi-matte camera target 
I did have some performance issues on the start. Especially the blacks 
showed a similar problem (L* varying between 7.4 and 11). Upon closer 
inspection however it turned out to be the result of a very slight 
(frankly invisible) contamination. After cleaning the results were very 
reproducible, also the L* values dropped. Perhaps cleaning is not even 
the right word. I rubbed the targets with my finger after which they 
looked a tiny bit "smoother". The midtones and higlights were much less 
susceptible to this effect.

So this probably points to the source of my problems with the EEM/Eboni 
targets. I have noticed before that the eboni prints are quite 
sensitive (note my remark on the printer rollers in the original post). 
I have done nothing special with the targets, neither handled them 
roughly, but also did not protect them in a special way. The have just 
been laying around for a day or two. But that's maybe not the way to 
deal with them.

Going back to the semi-matte camera target, another, slightly related 
explanation could be that I did not actually clean the target, but put 
some tiny bit of grease on them with my finger, thereby "polishing" it. 
In that way, it might be on optical effect, perhaps similar to the 
difference between matte and glossy papers. Then again, it would be an 
inherent effect of the matte print.

Does this make sense to anyone? 
 
Joost