Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,702   Posts: 1,548,444   Online: 1011
      
Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 32
  1. #21
    smieglitz's Avatar
    Join Date
    Oct 2002
    Location
    Kalamazoo, Michigan, USA
    Shooter
    Large Format
    Posts
    1,864
    Images
    97
    Quote Originally Posted by nworth
    I don't think it really applies, or at least I don't think it applies yet. For alternative processes...
    It sure applies to new TMAX 100. It has become pretty useless for alternative process printing IMO.

    Exposures will be longer, but probably not excessively so.
    That's relative. If you are enlarging with an average exposure of 20 seconds, losing 3 stops because of the film base makes your new exposure 2 minutes 40 seconds. That's tolerable. But, if you are contact printing using UV and your exposures average 20 minutes with the new film base you are now looking at 2 hours and 40 minutes for the exposure.

    And, I don't suspect the slight sensitivity of these print emulsions will be impacted much by the blue exposure. They are proportionally less sensitive to blue than to UV IIRC so the visible exposure won't compensate for the loss of the UV exposure.

    Quote Originally Posted by sanking
    If the new UV support base is anything like the base of the new TMAX-100 your speculation is entirely wrong. I tested the new TMAX-100 film with various light sources, including BL and BLB tubes, and with a NuArc 261K that produced a lot of radiation in the visible spectrum. In evey case the end result was a loss of printing speed of about three full stops compared to other films.
    Sandy, BTW the VDB test I posted earlier was also done with a Nu-Arc 26-1K but with that process it appears the loss in printing speed was slightly more than 2 stops. With which processes did you test the various exposure sources and find a three-stop loss?

    Joe

  2. #22

    Join Date
    Jun 2004
    Shooter
    Multi Format
    Posts
    145
    Images
    2
    I haven't printed anything from negatives shot on the new Tmax 400 order - but I have processed a couple of 8x20 negatives (yes, blowing a $9 sheet to test each side of each holder is excessive, but it's all I had) to test a batch of new filmholders and popped them under my 361T densitometer in UV mode - there is NO problem.... It's just the same TMY as it always has been - excellent UV transmission. Don't panic Clay...

  3. #23
    clay's Avatar
    Join Date
    Nov 2002
    Location
    Asheville, North Carolina
    Shooter
    Multi Format
    Posts
    1,118
    Images
    8
    Thanks! That is good enough for me. I use the same densitometer, and I have found it to indicate UV transmission density very accurately.
    I just want to feel nostalgic like I used to.


    http://www.clayharmon.net - turnip extraordinaire

  4. #24

    Join Date
    Oct 2005
    Shooter
    8x10 Format
    Posts
    275
    Quote Originally Posted by sanking
    So the alcohol soak is not very effective in removing the UV filter?

    Sandy
    Sandy:

    Will the ULF-28 put out enough UV light to shorten the exposure times?

    -R

  5. #25

    Join Date
    Aug 2005
    Location
    Los Alamos, NM
    Shooter
    Multi Format
    Posts
    2,055
    Quote Originally Posted by sanking
    If the new UV support base is anything like the base of the new TMAX-100 your speculation is entirely wrong. ...

    Sandy
    I haven't tried contact printing the new TMX. The increase in exposure that Sandy notes doesn't make sense to me, but I trust his work. Three stops could, indeed, be bad for alternative processes. Someone noted that TMY has pretty normal transmission in the UV and should print normally. That agrees with my experience. But TMX and TMY are different beasts, and TMX may have changed bases if a new batch was made.

    One question that has arisen is what and where the filter is. If it is separate and on the back, you may find a solvent for it. If it is on the film side, dissolving it may be a problem. If it is the base itself, you're out of luck.

    Aromatic compounds have very high extinction values in the UV, 30000 or more being common. The extent of the problem will depend on what the cutoff wavelength is. Generally the cutoff is pretty sharp, but the slope and spikiness in the spectrum may have a little effect too. I recall that naphthalene derivatives have a praticularly long cutoff. Many even appear yellowish. APS films used a polynaphthalate base. It had many advantages, including staying flat and dust free. Could this base have migrated to LF?

  6. #26

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by nworth
    I haven't tried contact printing the new TMX. The increase in exposure that Sandy notes doesn't make sense to me, but I trust his work. Three stops could, indeed, be bad for alternative processes. Someone noted that TMY has pretty normal transmission in the UV and should print normally. That agrees with my experience. But TMX and TMY are different beasts, and TMX may have changed bases if a new batch was made.

    It was pretty shocking to me as well when I found that the transmission loss was on the order of three full stops for the new TMAX-100 film. As best I can remember Clay and I were among the first to realize the change, and our findings were later supported by specrophotometer tests done by a scientists the RIT who came to his finding independently of our work.

    No question about it, even with light sources that produce a lot of radiation in the near visible and visible range the loss is about three full stops.

    Sandy

  7. #27

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by reggie
    Sandy:

    Will the ULF-28 put out enough UV light to shorten the exposure times?

    -R
    No, the ULF-28 puts out its radiationi in the same area of the UV blocking so in spite of the fact that it is a a faster printer than most commonly used light sources three stops light loss is too mucn of a handicap to overcome.

    Sandy

  8. #28
    TheFlyingCamera's Avatar
    Join Date
    May 2005
    Location
    Washington DC
    Shooter
    Large Format
    Posts
    8,392
    Blog Entries
    51
    Images
    438
    For a light source that might work for you, look into the Kino-Flo fluorescent lightbanks. They're not cheap, but you can get them with EIGHT 75w BLB tubes. In the Intro to Platinum class I took at CFAAHP with Carl Weese, we were getting 1 - 1.5 minute exposure times with the lamps at full power. Cutting the power to all tubes by half brought the exposure times down to 2.5 - 3 minutes. The 8 tube unit would be big enough to print 20x24.

  9. #29
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,069
    Images
    65
    A wedge spectrogram of Azo paper indicates to me that it has about 1/2 of its sensitivity in the blue region. Tests of cyanotype and other alternative process materials show little or no sensitivity in the blue region.

    We could run some tests at my workshop with the AgCl emulsion that I make to see what proportion of the sensitivity is in the blue and what is in the UV, but that differs from real Azo, in that Azo has other ingredients to enhance speed to visible light.

    Bottom line, Azo users will see this to a lesser extent, I think, than cynaotype printers. IDK about VDB or Pt/Pd printing. I'll have to test it I suppose. I really don't want to though.

    PE

  10. #30
    c6h6o3's Avatar
    Join Date
    Oct 2002
    Shooter
    Large Format
    Posts
    3,182
    Images
    6
    Quote Originally Posted by Photo Engineer
    Bottom line, Azo users will see this to a lesser extent, I think, than cynaotype printers.
    The problem for me in printing Tmax 100 negatives on Azo is not the loss of speed but the complete lack of contrast. Flat, flat, flat no matter what I do.

Page 3 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin