M1 measurement mode
M1 measurement mode
- Subject: M1 measurement mode
- From: Roger Breton via colorsync-users <email@hidden>
- Date: Wed, 12 Jun 2019 17:33:50 -0400
Dear ColorSync List,
Today, I was working on an Epson 7890 printer at a client.
According to my automated spectrophotometer, the measurement I got off my
client proofing substrate was :
> 95 0 -2.3 in M0
I know I have a choice of M0/M1/M2 CIE Lab coordinates off this instrument.
But in the heat of things (I had all kinds of troubles.?), I did not pay
attention to the possible differences between each and stuck with M0.
My handheld instrument (tungsten illumination M0 only) gave me :
> 95 0 -3.5.
A higher negative b* value. I know, it is not a huge difference.
In general, does M1 "reduces" fluorescence, much like "M2" UV filtering or
does it "increase" its value?
In "theory", I would think that M1 makes an optically brightened paper more
"b* negative", so that, an M0 instrument, which does not stimulate much UV
fluorescence in the 360nm range, would give a b* = -3.5.
But what is the "real" story behind M1? Is it to cause the substrate to
fluoresce "more", by throwing more UV energy at it? Therefore, causing the
b* to be "higher" than -3.5? Like -5.00 or -6.00?
Or is it supposed to yield a b* less than -3.5, as in the case of this
proofing paper?
I confess I have to do additional readings on the subject.
(I can be such a newbie at times.)
But here is what I do *know* will happen, from experience : if the substrate
appears more bluish (higher b* negative value), because of M1 higher UV
illumination, therefore, the proof will appear more "yellowish", in Absolute
Colorimetry, that has always been my experience, for a Source print process
that has a b* closer to zero.
But if the substrate appears "less bluish", because of M1 illumination, then
the proof will appear less yellowish, in AbsCol.
Does that make any sense?
I really need to brush up on my understanding of M1.
Thank you in advance for your patience and help.
Best / Roger
www.graxx.ca
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