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

[Francesco Fragomeni]

My issue is that most of the information I'm finding is just speaking in
general terms rather then specific empirical measurements. Most sources talk
about increasing development to achieve greater contrast or exposing one way
or the other. All of that is nice but lacks any actual measurements. Now I'm
very visual in how I work but having numbers to back you up can really be
quite effective in reinforcing the visual decisions being made. Thats why
I'm interested in ideal density numbers for platinum and its why some of the
points Etienne touched on were of interest to me. I know I need a neg with
more contrast and I know how to achieve that. I'm trying to get away from
generalities. I want to know actual density measurements so that I can use
my densitometer to read my negs to confirm that I am achieving what I want.
I'm trying to use the empirical measurements as a reinforcement and
supplement to my visual process.

I hope that makes sense and I don't sound crazy.

-Francesco

On Sat, Oct 8, 2011 at 3:12 PM, Francesco Fragomeni
<fdfragomeni at gmail.com>wrote:

> 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
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>>  >> ______________________________**_________________
>> >> Alt-photo-process-list |
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>> >>
>> >
>> >
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