Digital BW, The Print

Peter,

You wrote:

>I have a 1280, and I've seen this "bump."  Its a place between the
>dark tones and midtones where a small change of tonality on the
>screen causes an abrupt change in the print.  ...
>  Which curves did you say were the least problematical?

The "warm" curve is the most problematic.  The problem is that, unlike
many/most of the drivers, we can't hold the toner curve (magenta ink spot,
green curve in the hextones) up to the top (meaning the toner ink is not
flowing at all) and then drop the curve very steeply only fairly far into
the shadow tones.  The 1280 PC (uncertain about Mac) driver appears to have
problems with the steepness of green curve that is needed to do this.  It is
most happy with mildly-sloped curves.

So, the best curves for the 1280 PC are those in the more neutral range.

>I'm wondering if we might be able to use the 1270 driver on the
>1280?

It might be worth trying that or the 1290 driver.  Both of these supported
very steep curves without much of a problem at all.

I think the 1290 is the best printer I've used.  I think most consider it
mechanically equal to the 1280 (except a voltage/power-supply difference),
but it appears to have a different driver.  With the 1290 warm curve the
green is held to 255 (no toner) until the last/darkest quarter tone, where
it then dives to the black corner (0,0).  Being able to write curves this
radical without glitches in the image is really nice.


Paul
http://www.PaulRoark.com