[Alt-photo] [Alt-Photo] Wet Plate Collodion Sensivity Filterfor Normal Film

David Pitcher pitcherd1 at msn.com
Sun Sep 10 17:56:36 UTC 2017


Rosco makes round UV pass filters that are not too expensive.  https://www.pnta.com/lighting/dichroics/rosco-permacolor-dichroic-filter-3660-double-coated-uv-pass/?utm_source=google&utm_medium=cpc&utm_campaign=shopping&gclid=Cj0KCQjwxdPNBRDmARIsAAw-TUkrsDXBeXYIxcqhK1iaaPfdxAmGXrOt7Y8wEcRAu4eXSiGDKvK9i1oaAlBREALw_wcB

Cheers,
David

On Sep 10, 2017, at 10:46 AM, Peter Marshall via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org<mailto:alt-photo-process-list at lists.altphotolist.org>> wrote:

A UV Pass Blacklite Dichroic filter such as shown in http://www.dichroic.org/ultraviolet_pass_filters.htm when used with an orthochromatic film would give a similar response to collodion. But at a cost - I don't think it gives prices on the site.

Any differences are more likely to be due to the UV transmission of the various glass elements in the lens used than the film. Different glasses have pretty different UV absorption, but I think few modern compound  lenses would have high transmission below 350nm.

Peter


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On 10/09/2017 01:29, Joseph Smigiel via Alt-photo-process-list wrote:
Mustafa,

Salted collodion is UV-sensitive well below 400nm and the sensitivity drops to almost nothing around 500nm. See the graph in this post on the collodion forum.

The transmission of quartz lenses and modern lens coatings may also be factors in the overall exposure.

An orthochromatic film emulsion may get you close to the collodion sensitivity, but I don't believe any filter will mimic the collodion sensitivity since a filter can only subtract rather than extend the range. IIRC, a Wratten #44 cyan will be about the best you can do if using panchromatic film.

Joe


On Sep 9, 2017, at 5:03 PM, Mustafa Umut Sarac via Alt-photo-process-list wrote:

I looked to wet plate collodion sensivity and it starts from 400 goes to
512. Mid zone is the most sensitive. Who can make me such a filter to take
same spectral picture on ordinary BW film ? And to what cost ?

Mustafa Umut Sarac
Istanbul
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