[pure-silver] Re: Multigrade without filter?

"Claudio Bonavolta" a écrit:

ATIPPETT@xxxxxxx a écrit:
I though that I had read using no filters with Ilford Multigrade IV papers was equivalent to using the #3 filter. 
With a tungsten light source, it is supposed to be a grade 2.
Note that Ilford Multigrade IV FB is harder by roughly a half grade than its RC counterpart. 

I found it to be #2 1/2 - but I can't remember which Ilford paper that
applies to. As Claudio mentioned the various Ilford papers aren't all
the same contrast.  Figure somewhere between 2 to 2 1/2.


changing the filter keeps mid-grays but affect both highlights and shadows


As seen here ... Real live HD curves:
http://www.darkroomautomation.com/support/mgivrc-hd.jpg
http://www.darkroomautomation.com/support/mgivfb-hd.jpg
http://www.darkroomautomation.com/support/mgivfbwt-hd.jpg

Densities above 2.0 tend to be bumpy because densitometer
readings are thrown off by motes of dust and irregularities
in the paper surface.

More interesting are Zone graphs - they give an instant
useful view of the contrast grades
http://www.darkroomautomation.com/support/mgivfb-zone.jpg
http://www.darkroomautomation.com/support/mgivrc-zone.jpg
http://www.darkroomautomation.com/support/mgivfbwt-zone.jpg
These graphs are normalized to zone system white - 0.05OD.
Un-normalized the graphs look like a game of pick-up-stix.

If deep blacks are your thing nothing seems to beat well developed
and selenium toned MGIV warm-tone fibre base, 2.5OD and it isn't
even breathing hard:
http://www.darkroomautomation.com/support/mgivfbwta130se-zone.jpg

Data generated with products from:
http://www.darkroomautomation.com/da-main.htm

Light source is a Beseler 45MX, condenser, #212 (?) bulb.

--
Nicholas O. Lindan
Darkroom Automation
A Unit of Cleveland Engineering Design, LLC
Cleveland, Ohio 44121

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