Digital BW, The Print

Jean-Marc,

the 810 is one of the workhorses in the photographic industry. Very sturdy, 
very reliable readings. Because they are common you can find them so 
cheaply on eBay. However, be sure to get the calibration kit. The instrument is 
useless without it. For more info - and other models - visit xrite.com

What the x-rite 810 is NOT: It will not do what a spectrophotometer will do, in 
analysing color and it will not calculate a dot gain (because it is not a graphic 
arts instrument).

What it does well:  reliable reads into shadows over 2.00 that a cheap spectro 
won't do, and the ability to read transparency densities (mostly useful for 
photographic process calibration).

Xrite makes instruments that provide dot gain  percents but I don't know if it's 
worth the extra money if you can't find them cheap on eBay. I have used a 
Digital Swatchbook to do dot gains, but not relied on it for plotting out gray 
scales to make profiles. It is possible to get the formula and use an 810 (or 
any densitometer) to calculate dot gain (somebody else here with more 
traditional prepress experience could help you).
Basically, you call your highest density 100% and your paper white 0% and 
then you calculate the difference between the ideal and the actual density for 
a given patch on a gray scale. 

....  or... you use any ICC profile making program to make you a profile for your 
grayscale output and use that in your proof setup in Photoshop (but not 
anywhere else). I haven't done this myself, but I believe others have. The 
catch is that a good profile-making program can be costly and not worth 
buying if you only need it for soft-proofing. I find that I can eyeball a dot gain 
curve if I have enough print samples to see highlights / midtones / shadows 
properly.

The other use for the 810, of course, is that you will be able to make your own 
grayscale profiles with IJC and get rid of canned profiles forever (just like any 
serious color printmaker has). If you are on a PC, this may have to wait until 
the Windoze version is released - or you buy a cheap Mac from eBay!!

Hope this helps.

Antonis



--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Jean-Marc 
Humbert" <humbertjm@y...> wrote:
> Hello everyone,
> 
> my wish:
> 
> - I still use Piezography with MIS FS on Epson 1160
> - and I still try to obtain by twicking the dot gain curve in PS a 
> picture on screen that matches the final print,
> 
> and I am not happy with the result... (and think that most of my poor 
> prints are due to the fact that I applied inadequate corrections on 
> my pictures as shown on screen).
> 
> Apperently, I read on the newsgroup that I had to go through a 21 
> step wedge print as analyzed by a densotimetre, the reference being 
> the X-rite 810 (I have seen a couple exchanged on e-bay for about 200 
> to 300 $).
> 
> Would someone on the list be kind enough to describe how to work with 
> a densitometre (or may be to link me to specific source of 
> information)? 
> 
> Is  the 810 the best product in order to obtain the adequate dot gain 
> curve for a correct representation of the print? Do I have also to 
> buy the calibration tools for the X-rite 810?
> 
> I am ready to spend an another 200/300 $ for having a correct picture 
> on screen, but is this densitometre a great deal for such very 
> specific job? Is it difficult to work with?
> 
> Thanks a lot for your help.
> 
> JM Humbert
> Paris, France