Datacolor User to User Support Group.

While waiting for my newly printet patches to dry I have done a few 
tests, mind you nothing you can do statistics on. Furthermore Im not 
quite sure how to interpret the numbers :)

Done with 2 older 225 patch papers, Epson Premium Semigloss, UC PK 
ink (K2). Identitical paper underneath. Measured targets K6, L6, M6 
on both papers in Lab values, before and after 3 defined scratches 
was applied, one on each target. That way I got 2 readings before and 
2 readings after each scratch. Mean values were calculated and 
subtractet, difference presentet below as positive Lab numbers 
representing the effect of the defined scratch.

Scratches are defined as follows:

1) Superficial scratch applied with nail. Compared to allmost all the 
older scratches from the 1005 Spectrocolorimeter these were generelly 
more visible and broader - but you will still have to look for them 
to find them.

2) Long thin deep scratch allmost - but not quite - penetrating the 
ink. Length ca 1cm, width ca 0.5mm, done with point of knife. Quite 
severe, that you will spot instantly.

3) Point penetration of ink and partly paper, in effect showing the 
underlying paper. Diameter ca 0.5mm, done with point of knife. 

**********

The Lab values in positive numbers representing the difference 
between a patch before and after a defined scratch:

1)  0.28   0.35   0.93
2)  4.71   0.18   1.28
3)  3.76   0.74   1.12

**********

Interpretation and conclusion: 

The light nail scratch value (1) should not give any visible effects 
when comparing with an non-scratched. However for some reason the b 
value is on the way to becomming unacceptable - I have a vague idea 
that a number around 2 is generelly acceptet as "too much". All in 
all fully acceptable, but if you want to know its the *best* profile 
you can get, you´ll have to make a new print. Bear in mind though 
that the nail scratch is more visible than the tracks after the 1005 
spectro.

Both the long thin deep scratch (2) and the point penetration (3) 
shows clearly unacceptable changes in L values - whereas the ab 
(color) changes are modest and acceptable (? see remark above). That 
the L value suffers the most is logically as the underlying white 
paper gets measured as well. As notet earlier the nr 2) scratch will 
be seen clearly even though its not penetrating - only allmost. And 
you will know its time to print a new target. The point penetration 
(3) could mimick one of those small white dust bodys floating around. 
You will see it, but will you avoid it? Brush your papers gentlemen!

Aint we having a ball this friday night?  8)

Kind Regards

Niels