Digital BW, The Print

> From: Roy Harrington <roy@...>

> 
> I get what you are saying, I just don't think its as desireable.  I think the
> relationship between values is much more important to overall effect rather
> than the absolute densities.  I think with your scheme you'd always have this
> extra step of trying to find and match up your dmin and dmax.
> 


Hi Roy et al

I believe in the relationship between variables also.  I also believe in the
LAB mantra and would like the relationship between variables to meet LAB
specs because you have sold me on the fact that it is the way the eye sees.

In my scheme, I don't have to find dMin and dMax - they are known as they
are in the current methodology.  "Matching them up" takes about 3 seconds.
With the current methodology, I have to "match up" the end points and all
points in between.  I could get what currently has to be done in with a soft
proof, a visual and imprecise realignment of two images on screen, in this
same 3 seconds.  Furthermore if my image is all in-gamut such as my simple
classroom example, I don't even have to do that.

The reason why the current method has to fall back on to soft proofing is
very very simple.  This is very important and is the crux of this
conversation.  (Anyone want any more "verys"?)  While the current process of
"linearization" involves linearization OF LAB values it does not linearize
TO LAB (over the dynamic range of the printer).  This has a number of big
ramifications: our workspace (even with LAB-Grey!) will never match the
print space and the gamma of our print space is different for different
papers meaning even those parts of the density spectrum BOTH papers are
currently capable of rendering will be rendered differently.  This is why a
value such as L=50 in the image will never print at L=50 nor even
consistently across various papers. (This would not be a big deal if we had
colorsync to manage the transition between these (linear) spaces but we
don't.)  As a result, we have to soft proof even to get an in gamut image to
print properly.

I admit I am asking you to do things differently.  Specifically I am asking
you to:

1.  Calibrate the RIP differently (TO lab, not OF Lab)
2.  This means you will need to look at step wedges a little differently
3.  Draw the curves that manage tonal compression (or currently fix the
RIP's tonal compression) differently

Actually a lot of people (most?) don't even worry about RIP calibration and
step wedges.  They simply rely on the work of others (I have no problem with
this) and so, for many, items 1 and 2 above are a non-issues.  With regard
to item 3, we who calibrate the RIP could simply distribute our "standard"
curves for each paper, much in the same way Paul Roark does. In this case
the workflow for most collapses even further.

This is change, yes.  But I believe it will result in a simpler, faster,
more visually intuitive and more precise workflow than the current.

Another very important point.  There is nothing in my proposed workflow that
results in or calls for "clipping".  The image file is not clipped.  The
gamut is not clipped.  You CAN clip if you so choose but this is your call.

(Note a wetroom photographer clips when he let's the non V zones fall where
they may and they fall outside the tonal range of the paper.  The only way
he can manage this is through dodging and burning.  We have dodging and
burning AND curves.)

Guys, I can't go on with this in this form.  If I could show you what I mean
with the aid of a few simple diagrams we would at least reach comprehension
(if not adoption!) much faster.  So why don't I do this.  I will write up
with the help of a few diagrams what I am saying and proposing.  I will give
it three simple headings:

1.  Steve's RIP Calibration (avoiding the word linearization!)
2.  Managing compression of the image file to printer tonal range
3.  Workflow summary

I'll try to note what I see are the key issues with the current system and
why these are overcome with my proposed method.  I'll send it to you by
email offline and you can either read it at your leisure or toss it in the
trash.  How's that?

Steve