Split grade filter choices for cold light heads

Discussion in 'B&W: Film, Paper, Chemistry' started by jstraw, Feb 6, 2007.

  1. jstraw

    jstraw Member

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    In the June 1995 issue of Darkroom Photography, Joe Englander, describing procedures for split filter printing recommends yellow/magenta filtration for dichroic/condenser heads and blue/green filtration for cold light heads.

    Do any here that use a cold light head and do split grade printing use the blue/green filters? Does it matter if one has already color corrected the lamp with a 40YCC filter?
     
  2. Dan Henderson

    Dan Henderson Member

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    I bought an old Aristo cold light head from someone here at APUG just to try out cold light printing. I presume it is the old style bulb, and I have not corrected it with the yellow filter. I split grade print with blue and green filters successfully. I am on Aristo's wait list for a new head that will have the corrected bulb, and am interested to see how the blue/green times will change.
     
  3. lee

    lee Member

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    I use blue and green the proper filter numbers are the Wratten Blue 47b and the Green 58 filters. Those filters will match the Aristo VCL 4500 two color heads. The newest one color head from Aristo is a V54 and you dont have to use the 40y filter for VC papers. The filters will work properly with the V54 light source.

    lee\c
     
  4. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council

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    AFAIK the CC40Y filter is for cold light heads that are designed to give blue light only (for graded papers). Mine is such a one, and I get normal contrast with MG filters, so I guess that would mean no problems in split-filtering, but I don't use that technique myself.
     
  5. jstraw

    jstraw Member

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    I'm thinking that whether I switch to the V54 lamp or not, I should give the blue/green system a try.
     
  6. jstraw

    jstraw Member

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    I plan to make that lamp switch when my budget can absorb it. Till then I'm filtering the old lamp. Aristo told me I need the D2-HI-V54 for my Zone VI head.
     
  7. Steve Sherman

    Steve Sherman Subscriber

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    The blue / green system of split printing is the "poor man's answer" to a dicro head or multicontrast cold light head. I know because I used the blue/ green system with inexpensive plastic gels myself.

    I'll try and make this as short as possible. Variable contrast filters are "Subtractive" in nature, that is to say they subtract or take away certain parts of the color spectrum, all the CC 40Y filter does is bring a strong blue cold light head back to a neutral color. This to becomes another subtractive filter, in conjunction with magenta multi contrast filters you have now added two filters, which add considerable length to your printing times.

    When you introduce a straight blue filter it becomes additive light, meaning you are just magnifying the intensity of the blue cold light. Blue light will maximize the contrast that the paper is capable of, yes there is density to the filter but it does not significantly increase exposure times. Likewise, with the green filter you are adding the color of light, which effects the lower contrast portion of the emulsion.

    Typically, you use these filters in conjunction with one another to effect very specific contrast too more localized areas of the print. Usually, one would "set the exposure" with the blue filter and then add whatever amount of green light is necessary to provide detail and information in the highlights. It is somewhat trial and error but should quickly allow you to dial in many difficult negatives to your liking.


    Lastly, I use plastic "theatre gels" made by Rosco above the negative. They are very inexpensive and easy to use. I use a deep blue #69 and medium green very similar to a #58 green filter. Total cost of a 2'x2' sheet was about $10.00 per color.
     
  8. resummerfield

    resummerfield Subscriber

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    I split filter with 58/47B filters, under an Aristo T-12 with the V54 tube, and it works fine. For split filter printing, I don't think it would make any difference what color filters you use, so long as the hard filter blocks green light and the soft filter blocks blue light, or what color the light source is (V54, the W series, or tungsten). The time given for the hard and soft exposures might change, but the results would be the same.
     
  9. jstraw

    jstraw Member

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    Alas, there's no way to switch between two filters with a Beseler 45MXT that wouldn't disturb the negative between exposures so I must filter below the lens.
     
  10. Steve Sherman

    Steve Sherman Subscriber

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    Unless of course you have modified your 45MX with a 7"x9" Aristo cold light head which now sits atop the negative carrier which has a 1/2" space between light and carrier.

    Sorry, I didn't remember what the 45 used to look like.
     
  11. jstraw

    jstraw Member

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    Steve, do you have a picture of that set up?
     
  12. Fotohuis

    Fotohuis Restricted Access

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  13. Steve Sherman

    Steve Sherman Subscriber

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    Sorry, I don't have a pix. Enlarger is still packed away while DR is under construciton.

    I'll try to find a standard pix and describe the setup, it is not too difficult to do.
     
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  15. jstraw

    jstraw Member

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    That would be great.
     
  16. Steve Sherman

    Steve Sherman Subscriber

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    I am not able to drag a picture of a MX over here.

    Very basically, remove the top section of bellows, where this support for the bellows bolts onto the sliding chassis I made a support which bolted onto the chassis in the same manner. An Aristo 7.5" x 9" Cold light sits over an opening which allows exactly a 5x7 negative to project through.

    When I began using the blue / green method of split printing I raised the cold light 1/2" about the aluminum support to allow the plastic gels to rest on top of the glass negative carrirer there by controlling the color of the illumination without impacting the projected image quality.

    Hope this helps
     
  17. jstraw

    jstraw Member

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    Hmmm...I have the upper bellows completely compressed...I don't make use of it. I didn't ever consider that it might be removable. I could construct a replacement for it that houses filtration, perhaps....

    I'll be examining the assembly more closely. What I'd like is a slide-through drawer that moves from left to right with three sections. Soft filtration/no filtration/hard filtration.
     
  18. Steve Sherman

    Steve Sherman Subscriber

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    That sounds like a great idea
     
  19. jstraw

    jstraw Member

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    I'll let you know what sort of prototype seems feasible after I've examined the assembly.
     
  20. Curt

    Curt Subscriber

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    I bought this extra Beseler 45 head to convert to a 5x7 and if I were to actually use a cold light head on it I would want to do split grade filtering. I have some heads, 4x5, 5x7, and 8x10. and the Aristo D2 on the 45m in my darkroom. They are all made by Aristo. I'm under the weather; can you tell me again what the reason for removing the top bellows, which is not used with cold light heads? Oh my I just answered my own question. A filter box goes there! I was thinking the upper bellows was under the negative holder. Duh! That sounds like about the only way to do it neatly. I don't have a glass holder, did I hear that someone had one in use with this filter system and is is necessary? This Beseler head part is for design/cutting/destruction/prototype purposes as I don't want to go to town on my working enlarger.

    What is needed is a 1/2 inch box of similar perimeter dimensions of the top bellows with slots or rectangular openings for a filter holder that will hold the filters and is light tight and allows the filters to easily slide into the the light path. Am I getting it right?
     

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  21. Steve Sherman

    Steve Sherman Subscriber

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    Great pix to illustrate how the light source is secured.

    The picture on the far right shows a side view of what I am talking about. The top portion which secures with two larger bolts is removed. I had an aluminum tray of sorts made which supports a 7.5" x 9" Aristo cold light, the light sits above the support on 1/2" spacers to allow each filter to be used as needed.

    The top piece of bright aluminum is removed and all that remains is the lower piece. This then becomes a hinged jaw which allows for a negative carrier to be inserted. I took a piece of thin picture frame glass and cut it to size to fit in above the "jaw". On top of the glass is the same size piece of white plexiglass (greatly reduces dust spotting). These two pieces are then hinged with tape.

    The key to it's success is black electrical tape is just slightly larger than the 5x7 negtaive. The black tape is outlined on both the glass and white plexi, when carrier is close the tape sits on top of one another providing a thin space between negatvie and plexi. WIth no downward pressure on the negatvie the negatvie just sits on the clear glass and virtually elimnates any Newton Rings, at least in my experience.

    With the added space the carrier creates when "jaw" is closed I took some foam insulation tape about 1/4" x 1/4 and adhere it to bright aluminum jaw. The tape also becomes the guide to centering the negatvie carrier under cold light.

    This may not look like a factory made set up, but it works perfectly with nice even illumination and abiltiy to split print with Roco theatre gels for very low out of pocket $$.

    Hope this helps
     
  22. jstraw

    jstraw Member

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    You just did all of my posting for me! You took the pics, you did the explaining!

    Yep the problem is that the upper bellows is not easily removable. It would have to be cut out of its frame. Yes, I'd be building a box with a drwaer for filtration that would be a direct replacement for the contracted, upper bellows. If I could get my hands on a second upper bellows assembly drom a beater enlarger to modify, I'd do it but I'm not going to cut the bellows out of my current assembly.
     
  23. Steve Sherman

    Steve Sherman Subscriber

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    The upper and lower metal supports holding the upper bellows are completely removed and could be saved so that all could be restored to orginal if one wanted.
     
  24. jstraw

    jstraw Member

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    What I'm envisioning is having the upper and lower supports for the upper bellows hold the box with the drawer, instead of holding the bellows. This would be ideal if the bellows could be removed from the supports easily, without damage but it looks like it's glued in place. I'd canibalize a second upper bellows assembly if I could get my hands on one but I'm not willing to damage the one that I've got.
     
  25. PKM-25

    PKM-25 Member

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    Revived old thread alert:

    I have a bit of confusion going on at the moment. I have been using a D2HI cold light on my 45MX, it has a strong blue-green cast, not overly blue, but kind of in the middle. I thought was getting decent contrast but in buying a second, new condition D2 lamp for lower light output and backup, the thing is straight up white, no color cast at all, the seller bought it new in 93, so I bet it is the updated V54 ( thank god ).

    So do I have the old W45 lamp in my D2HI or the new V54? I have no idea. Also, where does one source a 40ccy gel? I looked at the list of Rosco ones at B&H and even called Rosco, they had no way of converting 40CCY to their standard of CTO. I have a feeling that my D2HI is the older lamp, so I will want to filter it when used…
     
    Last edited by a moderator: Mar 7, 2012
  26. ic-racer

    ic-racer Member

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    This is how my bulb was marked:
    [​IMG]

    This is the yellow filter I used (it is 30cc):
    [​IMG]
     
    Last edited by a moderator: Mar 7, 2012