Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,483   Posts: 1,571,211   Online: 1110
      
Page 8 of 8 FirstFirst ... 2345678
Results 71 to 80 of 80
  1. #71
    lee
    lee is offline
    lee's Avatar
    Join Date
    Nov 2002
    Location
    Fort Worth TX
    Shooter
    8x10 Format
    Posts
    2,913
    Images
    8
    Peter said, "Originally it had appeared that calibrating my meter might mean that I’d turn my ASA all the way down to .32—it is of course presently turned to .68. So if I dialed in .50 (Does that sound right Lee?) on my ASA dial the film would be exposed slightly longer AND my development time would be shorter yet i.e. less than 5m45s."

    Peter,
    Yes, ei 50 should be about right. IF you are looking to print on Grade 3 paper then yes the development would be a little shorter. This is FP4 and I think this film is a little contraster than its faster sister HP5+. Go ahead and make a contact print sheet of the frames. Set the enlarger height to an 8x10 and leave it there for all the tests and subsequent printing. Use a grade 3 filter. Make a test strip in 2 second increments across the paper. Where the film is in contact with the paper and really look closely at the blacks in zone 0 and at the film edges. Find the first "real"or Maximum black and use that time for the contact print. Now you have a strip that should represent all the zones. If you are losing some frames to either too black or too white, look at the test strip and reevaluate your choice. If it is too black then adjust your time shorter and conversely for too white lengthen the exposure time. Remember that the zones above zone VIII will in all likelihood not show anything but white. This is to be expected and ok. There should be a difference in Zone III and zone II and a very slight difference in Zone II and zone I. Make the next print with a grade 2 paper after you run that Maximum black test again. This will show you how your camera and film and developer will react with the paper and the enlarger. good luck!

    I think I might be tempted to shoot a roll of "real" images and develop them to your new time shot with the ei of 50. Use the enlarger height you were using and use the exposure time that you found for the contact prints. Let's see what happens now. Try it with the grade 3 time and grade 3 filter and then use the grade 2 filter and grade 2 time so be sure to note them and write them down. When making the real photos if a person is involved make that skin zone VI if that caucasian. To do that meter the skin and open up one stop. again good luck. You are now one your way to discovery of photography at a very different level than you were 2 weeks ago.

    lee\c

  2. #72

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    Peter,
    To reply to your question of the effects of negative density on paper grades. Also to reply to your question of the combined effects of longer exposure and development time as it relates to eventually printing on grade three paper.

    First of all, the higher your zone VIII (greater contrast of the negative)density the lower contrast the paper that it will be printed on. If you can picture this in your mind, proper degree of contrast that one realizes in a print is a combination of film contrast and paper contrast. Contrast is a "whole" and not two disparate parts. The film contrast and the paper contrast are irrevocably linked. Therefore if we develop a film to a Zone VIII density of approximately 1.40 we would need to decrease the paper contrast to offset the high contrast of the film negative. If we lower the film negative contrast to 1.10 then we would increase the paper contrast to bring about the desired result. I hope that this answers this question for you...please readdress the question if I have failed to explain it to your understanding.

    If you were to lower your film speed to 50, you are correct in that the longer exposure would increase the low (Zone I) density. Yes it would correspondingly increase the Zone VIII density as well if your present developing time, temperature, and agitation remain the same. However what we need to do is decrease the development to decrease the higher (Zone VIII) density.

    Therefore, if you decrease your film speed to 50 (increase film exposure) with Ilford FP4 and decrease your development time to 5 min 15 seconds (decrease negative contrast) you will probably find that your negatives will print on grade three paper (higher contrast paper to offset lower negative contrast).

    Now the matter of evaluating the tonal range and paper grade match on your enlarging paper. This is where you are getting conflicting direction. It is possible to try several ways of evaluating this...I am not sure that they are equal in my experience. What I have found is that if I try to match maximum blacks at this stage then I am prone to making an error of as much as one zone. Why? because human eyes do not distinguish tonal variance in the darker tones as easily as they do in the higher tonal ranges. Compounding this inherent tendency is the fact that those tone lie on the papers shoulder region and are actually more closely coupled then the mid ranges. If we were to try to match the lighter tones at this point then we are dealing with a matter of better visual acuity, certainly, but the high tones are located on the papers toe...again not as well separated as the mid tones. So I stand with my earlier recommendation of getting your film negatives to match a zone V tonality to an 18% gray card. We know that Zone V should correspond to that tonality since our film is exposed for that and if the tone is too dark then we have exposed the paper too long and if too light we need to add more enlarger exposure. Once we have matched that tonality we will have a clear picture of how the other negative densities match the enlarging paper's grade selection.

    If your were to match your Zone V tonality to an 18% gray card, and found that your blacks were not separated below Zone III and your whites not separated beyond Zone VII on a grade three paper then you would know that your negative contrast is too high. If you conversely found that your blacks showed noticeable tonal separation between Zone I and Zone II and that your whites showed marked tonal differentiation between Zone VIII and IX then you would know that your negative contrast is too low. These are indications that the negative development time needs to be adjusted for the paper grade selection. Another thing that I wish to stress is that one should not attempt to evaluate these tonal representations on wet paper. Paper dries down...in other words what may appear as base paper white on wet paper will dry down to a darker tone. This is more of a factor on the lighter tones then the darker tones. Please remember this exercise is not about getting a bunch of numbers down on a piece of paper or committed to memory. It is about getting a given scene luminance to a given tonal representation not on film but rather on paper.

    As I previously stated, this is not about arriving at proper negative printing exposure at this time. It is about matching your negative contrast to a given grade of paper. Once this is done, then we can move on to proper printing exposure considerations for an actually photographed scene.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  3. #73

    Join Date
    Mar 2003
    Posts
    28
    Thank you David and Lee. And Don, yes I was able to follow your post. Although I’ll have to admit that I’ll need to take your explanation with me tomorrow or I’m sure to go off track.

  4. #74

    Join Date
    Mar 2003
    Posts
    28
    Well I went in today and printed some contacts. Good news and bad news. At 15 seconds, with a #3 filter I got what I thought was a good Zone V print—paper machine dried. But when I got home I saw that the photo company had started their read, one negative late—meaning they began to read on Zone I instead of Zone 0. That means that my Zone V densitometer reading was in fact 89 rather than 102.

    So I was looking at the wrong frame (IV) when I decided 15 seconds was my burn time. But I think when I redo it tomorrow with increased times it will still come out pretty well. Burning one frame off i.e. burning for frame Zone IV instead of V I got nice incremental steps on my lower zones ( I, II & III). Though I wonder if I won’t loose at least Zone I with increased time. I got nice steps on Zone VI and VII and just a tiny hint on VIII.

    I would guess that an increase of 3 to 4 seconds will give me the correct tone in the correct frame tomorrow and then I'll check my other frames and decide if I need to go to a #2 filter.

    I’m sure I’ll get this tomorrow and I really want to thank all of you for your time and advice. Thank you very, very much.

  5. #75

    Join Date
    Mar 2003
    Posts
    28
    Whew, well, just got home.

    It appears that with a grade #3 filter that 18 seconds will give me…
    1. Subtle steps between Zone V and II but that beyond that it goes to max black.
    2. Subtle steps between Zone V and just a touch of tone on VIII but white after that.

    Using a grade #2 filter…
    1. Subtle steps between Zone V and Zone 0. Then it goes to max black.
    2. Subtle steps between Zone V and Zone VIII (just a hint of tone at VIII you understand) with white after that.

    So it would seem that I need to cut my development time by I think 30 seconds more to truly come into the #3 filter zone. It also seems to me that now that I have a “master” roll of negatives for a #2 filter I can go to any school and shortly after calibrate my film to that enlarger. The same would be true for paper if I were inclined to change (which I’m not but just theorizing).

  6. #76
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,433
    Images
    20
    Sounds like you're really getting things under control!
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  7. #77

    Join Date
    Mar 2003
    Posts
    28
    Yes... and it's about time too some would say since i've been out of control for years now! <grin>

    I went to take some pics of an old ship today but the gate was locked. I'll be moving ahead now. I really can't tell everyone how much I appreciated their time and advice.

  8. #78

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    Peter,

    I am happy that we could help. Good luck to you and have fun.

    Best regards,DM
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  9. #79
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,433
    Images
    20
    If anything, this discussion reveals that it's not really that hard, and there are enough people around here who do this kind of testing, each with small variations, that we could all take turns explaining it, and it still all made sense.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  10. #80
    Aggie's Avatar
    Join Date
    Jan 2003
    Location
    So. Utah
    Shooter
    Multi Format
    Posts
    4,925
    Images
    6
    ..

Page 8 of 8 FirstFirst ... 2345678


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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