[alt-photo] Re: Your Approach to Making Negs for Platinum Printing? Ideal Negative Contrast and Dmax?

[Francesco Fragomeni]

I found some links to what look like much better archives. I'll start
digging. Thanks as always Don!

I'm still hoping Etienne can expand a little bit on the densitometer density
range bit of the converasation.

-Francesco


On Sat, Oct 8, 2011 at 2:56 PM, Don Bryant <donsbryant at gmail.com> wrote:

> You can start with this one here below by former list member Carl Weese
> (co-author of 'The New Platinum Print'):
>
>
> http://theonlinephotographer.typepad.com/the_online_photographer/2010/04/the
> -making-of-a-platinum-print-slideshow.html
>
>
>
> -----Original Message-----
> From: alt-photo-process-list-bounces at lists.altphotolist.org
> [mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf
> Of
> Francesco Fragomeni
> Sent: Saturday, October 08, 2011 5:34 PM
> To: The alternative photographic processes mailing list
> Subject: [alt-photo] Re: Your Approach to Making Negs for Platinum
> Printing?
> Ideal Negative Contrast and Dmax?
>
>  Don,
>
> I must be looking inthe wrong places. I figured there must have been plenty
> of this discussion before. I'll look through the archive link I have. Maybe
> I have a weird link or I just want paying attention. I'll look through it
> all again.
>
>
> -Francesco
> On Sat, Oct 8, 2011 at 2:29 PM, Francesco Fragomeni
> <fdfragomeni at gmail.com>wrote:
>
> > Etienne,
> >
> > Wow! Thanks for all for all of the info. I'm only working with large
> format
> > negatives (I shoot 8x10 and larger) in this case so my follow up is in
> > regard to what you posted regarding in-camera negatives and not the extra
> > digital stuff.
> >  "Below are some observations I have made in the past (you will find
> > others in the list archives, from me and others).  For the traditional Pt
> > process, you want a negative with a density range ("DR") of 2.0 or higher
> (I
> > generally aim for 2.4) to get both Dmin and Dmax in the print.  Note that
> > not all films available today will produce such a DR, no matter how you
> > expose and develop them.
> > BTW, I encourage everyone to stop speaking of "stops" and "contrast
> range"
> > -- much better to identify clearly what you mean and speak of "exposure
> > scale" ("ES") and "density range" ("DR"), to make sure we are always
> keeping
> > the distinction in mind.  On this, see my message of 11 Oct 2009, in the
> > archive.  For example, while the ES of traditional Pt is around 2.1 to
> 2.4
> > (and, therefore, a negative that produces a full-scale Pt print will have
> a
> > DR of 2.1 to 2.4), the full-scale DR of the Pt print itself is much lower
> --
> > only 1.4 to 1.7 (the latter only with heroic efforts)."
> >
> > I definitely agree with what you're saying. I often get confused with all
> > of the different terminology. When you say DR do you mean the range
> between
> > FB+F and the most dense tone in the negative? I have a X-Rite
> transmission
> > and reflection densitometer at home and I'm unsure of how to read a neg
> to
> > determine is DR or a prints ER. Is it simply reading most dense area and
> the
> > least dense area and taking the difference? My processes are always much
> > more visual then technical but I'd like to grasp an understanding of how
> to
> > make all of these measurements so that I can empirically understand what
> I'm
> > visually seeing and doing.
> >
> > I am specifically interested in figuring out how to properly measure the
> > density range in a negative so that I can match my visual understanding
> of
> > what these negatives look like to the actual measurement of the negatives
> > density range. I hope that makes sense. I suppose I'm just looking for a
> > little clarification on the best practices for using a densitometer and
> how
> > to relate the measurements to density range and exposure scale.
> >
> > Thanks so much for the help!
> >
> > -Francesco
> >
> >
> >> Francesco wrote:
> >>
> >>   Now that I'm
> >>> venturing fairly aggressively into platinum, I'm very interested in
> >>> hearing
> >>> how you all approach making your negatives for platinum. I'm speaking
> >>> specifically about in-camera negatives (no digital negs or other
> >>> processes
> >>> here). Achieving the ideal contrast for platinum is what I'm interested
> >>> in.
> >>> For silver, a negative with a contrast range of around 3.5 stops will
> >>> print
> >>> well on a grade 2 filter or paper. There is also a ideal negative dmax
> >>> that
> >>> some people use as a standard to shoot for but I'm not sure what that
> >>> number
> >>> is. As I understand it, platinum calls for greater contrast to take
> >>> advantage of the longer tonal range of the platinum process.
> >>>
> >>
> >> Below are some observations I have made in the past (you will find
> others
> >> in the list archives, from me and others).  For the traditional Pt
> process,
> >> you want a negative with a density range ("DR") of 2.0 or higher (I
> >> generally aim for 2.4) to get both Dmin and Dmax in the print.  Note
> that
> >> not all films available today will produce such a DR, no matter how you
> >> expose and develop them.
> >>
> >> BTW, I encourage everyone to stop speaking of "stops" and "contrast
> range"
> >> -- much better to identify clearly what you mean and speak of "exposure
> >> scale" ("ES") and "density range" ("DR"), to make sure we are always
> keeping
> >> the distinction in mind.  On this, see my message of 11 Oct 2009, in the
> >> archive.  For example, while the ES of traditional Pt is around 2.1 to
> 2.4
> >> (and, therefore, a negative that produces a full-scale Pt print will
> have
> a
> >> DR of 2.1 to 2.4), the full-scale DR of the Pt print itself is much
> lower
> --
> >> only 1.4 to 1.7 (the latter only with heroic efforts).
> >>
> >> ==========
> >>
> >> There are two things at work here: (i) matching the negative density
> range
> >>> ("DR") to the printing exposure scale ("ES"); and (ii) the character of
> the
> >>> exposure scale, however long or short it is.  If the DR of your negs is
> too
> >>> short to match the printing ES, you'll get low-contrast prints with
> murky
> >>> (but not very deep) shadows and/or fogged-looking highlights.  But even
> if
> >>> the negs have the right DR for the process, the characteristic curve of
> the
> >>> printing process may be ugly.
> >>>
> >>> The standard long-scale Pt process has a very, very long linear scale
> >>> with symmetrical, gently rounded toe and shoulder, typically printing
> the
> >>> whole step wedge with some scale left over.  Therefore, you need to use
> >>> negatives with a very high DR to obtain all of the available print
> zones
> >>> with this process.  Photographers have not typically made negatives
> this
> >>> "bulletproof" since the late 19th Century, so folks have tried a number
> of
> >>> different methods to shorten the Pt exposure scale (adding dichromates,
> >>> hydrogen peroxide, etc., etc.).  These tricks shorten the exposure
> scale
> by
> >>> raising the threshold exposure -- not really a very promising way to go
> >>> about it.  Anybody who has done serious sensitometry with the process
> has
> >>> seen the ugly characteristic curves the short-scale versions of the Pt
> >>> process produce.  I have yet to see prints made using any short-scale
> Pt
> >>> process that came close to the look of "real" (long-scale) Pt prints.
> >>>  Unfortunately, so many workers are using the short-scale processes now
> that
> >>> many people don't even know what a good Pt print is supposed to look
> like.
> >>>
> >>> I commend to you an experiment:  Make some in-camera negatives with a
> DR
> >>> above 2.1 (try to hit 2.4 for starters), and print them using the
> standard
> >>> full-scale Pt process.  I bet you never go back to digi-neg Pt printing
> >>> again, and depending on how big you think prints need to be, that you
> >>> acquire one or more LARGE format cameras or learn to make good enlarged
> >>> negatives in the darkroom (not so easy now that slow, blue-sensitive
> copy
> >>> films are long gone).  If you have no option besides digital, have a
> service
> >>> bureau make some 2.4 DR negatives with an imagesetter using your files.
> >>>
> >>
> >> ==========
> >>
> >> Think of it as mapping.  The scene you photograph has a certain range of
> >>> luminance values.  You want to translate, or "map," these luminance
> values
> >>> to useful negative densities, which can in turn be mapped to the
> available
> >>> reflection densities of your chosen printing medium.
> >>>
> >>> To do this, we start with the exposure scale ("ES") of the printing
> >>> medium.  Using calibrated step wedges, we see what range of exposures
> gives
> >>> the full range of printed tones the medium is capable of producing --
> any
> >>> more exposure is indistinguishable from the blackest tone, and any less
> >>> exposure is indistinguishable from the lightest tone (paper white, or
> close
> >>> to it).  Now, if we want the full range of tones the process is capable
> of
> >>> producing to be represented in our print [which may not always be the
> case],
> >>> we know that our negative must have a density range ("DR") equal to the
> >>> printing medium's ES.  So, we arrange to translate the luminance values
> in
> >>> the scene to the particular negative densities that will produce the
> print
> >>> tones we want to represent each scene luminance value.
> >>>
> >>> Not so long ago, we did this by adjusting our exposure and film
> >>> development, and then perhaps reducing or intensifying the negative or
> >>> masking it for printing, and finally by dodging and burning as we
> printed.
> >>>  It sometimes took all that, because we have to condense or compress
> the
> >>> 1,000,000:1 luminance range of the scene we photographed (this is about
> >>> normal for a sunlit scene) down to the 100:1 (or less) density range
> that a
> >>> print can reproduce.
> >>>
> >>> These days, people who print digitally can use Photoshop to adjust the
> >>> mapping from the as-captured (or as-scanned) image file to the negative
> that
> >>> will be used to make the print.  This is much easier, and also much
> more
> >>> flexible, than doing it chemically or with masks.  However, the goal is
> the
> >>> same -- to translate or map certain luminance values in the scene to
> the
> >>> desired print density values, using the negative as an intermediary.
> >>>  Applying curves is how we do this.  It's fundamentally the same as
> using
> >>> the Photoshop tonal controls (levels, brightness/contrast, whatever) to
> >>> adjust a digital capture for the desired print values (i.e., if you are
> just
> >>> printing digital images on paper), with two added wrinkles: (i) you
> have
> to
> >>> understand how the characteristic curve of the printing process
> responds
> to
> >>> the negative values, and (ii) you have to be able to imagine how to "do
> it
> >>> in reverse" since you are working on a negative -- if you want the
> shadows
> >>> to have more contrast in the print, you have to increase the contrast
> in
> the
> >>> lightest parts of the negative.
> >>>
> >>> In theory, you can map any scene luminance value (or digital
> >>> representation of a scene luminance value) to any available print tone
> (with
> >>> the caveat that the curve should be monotonic -- never reversing slope
> --
> >>> unless you are after special effects reminiscent of the Sabattier
> effect).
> >>>  In my view, there is no substitute for learning enough
> >>> sensitometry/densitometry to really understand how the mapping works,
> and
> >>> then to test your processes to see how they distort the mapping so you
> can
> >>> correct for it.  It's not very difficult, and once it is mastered you
> will
> >>> truly have the chops to get what you want out of your photographs.
> >>>
> >>> So, all that said, back to curves destroying negative content.  Mapping
> >>> is mapping -- the person who wants to represent the surface of the
> earth
> on
> >>> a flat surface has choices to make, because there is no way to linearly
> >>> reproduce the surface of a sphere on a flat surface.  And as we learned
> in
> >>> grade school, cartographers have come up with hundreds of different
> ways
> to
> >>> do it, each one good for some particular task.  If you want to be able
> to
> >>> visualize comparative land areas, you use a different projection than
> if
> you
> >>> want to determine bearings from one place to another.  The same is true
> for
> >>> mapping tonal values in photography.  So, the "right" curve is the one
> that
> >>> produces the results you want -- i.e., the one that maps the scene
> luminance
> >>> values to the print densities you want.  In general, one way I'd advise
> >>> folks NOT to do this is to copy someone else's curve "because you're
> using
> >>> the same process."  No two people ever use the "same" alt process,
> because
> >>> there are way too many variables to control.  And no two monitors are
> the
> >>> same, or scanners, or printers, or Pt "emulsions," or coating
> techniques, or
> >>> anything else you use to make prints.  So, the only way to end up with
> a
> >>> useful curve for your process flow is to test and figure it out for
> >>> yourself.
> >>>
> >>> Generally, one would like to calibrate one's monitor, then build a
> curve
> >>> for each printing process one uses so one can just adjust the image on
> the
> >>> monitor (as a positive), then let the computer figure out what negative
> >>> densities are required to map the monitor view to the final print
> (though
> >>> once again, the monitor has a considerably greater luminance range than
> a
> >>> print has density range, so it will be a "rendition" of the monitor
> image,
> >>> not a literal copy).  Only you can build such a curve, after doing the
> >>> sensitometry/densitometry on your equipment and printing processes.
> There
> >>> are aids available, but IMO one is much better off gaining an
> understanding
> >>> of the fundamentals and just doing it -- just as people who really
> >>> understood what they were doing always got better results than people
> who
> >>> "learned" the "zone" system by rote.
> >>>
> >>> So, if you have a curve that really does translate (transliterate ??)
> >>> from your monitor to your prints, great -- it is not destroying
> anything,
> >>> but rather helping you to map values from your digital image file to
> the
> >>> final print, thereby allowing you to do your image adjustment by eye
> rather
> >>> than by figuring.  But if your curve doesn't produce prints that are
> >>> pleasingly rendered based on the screen image, you need to change
> something.
> >>>  You can futz around with the process to try to match it to the curve
> you
> >>> have, but that's the hard way (and you may well not ever find a
> variation
> >>> that works as you'd like).  Better to adjust your printing process
> until
> you
> >>> get the most linear scale you can (for reasons I won't go into here,
> having
> >>> to do with producing the smoothest tonal range), then developing a
> curve
> >>> that translates from your monitor to your prints.
> >>>
> >>> The problem with the "short-scale" versions of Pt is that they have
> much
> >>> less linear tonal ranges than long-scale Pt.  You can successfully map
> this,
> >>> if you work at it, and thereby get correct overall tonal rendering by
> using
> >>> a curve that compensates for the nonlinearity.  However, you still
> won't
> get
> >>> the smooth transitions that long-scale Pt can produce.  And since the
> >>> gorgeous tonal rendering is the real draw of Pt in the first place, why
> >>> settle for something less just because one would prefer to avoid
> dealing
> >>> with how to make digital negatives of sufficient DR?  Particularly
> given
> the
> >>> cost of the Pt process, I just can't see why one wouldn't use it to its
> full
> >>> advantage -- which IMO requires using the long-scale process.
> >>>
> >>
> >>
> >> Best regards,
> >>
> >> etienne
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
>  >> ______________________________**_________________
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> >>
> >
> >
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