Education development test..

Discussion in 'Film and Processing' started by peter_korzaan, Jun 27, 2013.

  1. I want to educate myself in a deeper understanding of development by changing the time duration and agitation, to see the differences in the final negative.
    I'm going to set up a print of Digital Dog's 'Printer Test File', (http://www.digitaldog.net/tips/) and shoot several single shot, exposures, using a large format camera, and then develop them in a single sheet developer I made out of 2" ABS pipe.
    Up to this point I have done a very standard developing, in getting my moves down with how I agitate, how often, ect, in D-76, keeping the time to that which was recommended.
    Today I will be getting my first bottle of HC-110 and want to conduct some experiments, to see the difference between the two, and also, develop for more contrast.
    Questions:
    1) What I understand is that more agitation, will give you more contrast, but do not understand what longer development time gives you.
    2) In experimenting with agitation... at my normal development method, I agitate for the first 30 secs, and then for 5 seconds every thirty seconds. In changing this, what do you suggest?
    3) In experimenting with time duration, what would you suggest for the amount of 'time' extension, or subtraction?
    thanks for your help...
     
  2. More time will give you more grain and more contrast. You usually make adjustments in 10% variables. I would keep my agitation scheme a constant if it were me, and vary my development time. D76 will give you different grain and contrast depending on whether you use it full strength or diluted 1:1 w/ water. Development times will be related to the temp that you use, which is why I would go w/ 10% as a safe way to monitor contrast adjustments. You can also just switch film and/or developers, or use lens filters, to get what you're looking for. Not long ago I accidentally used the times for full strength D76 and Tri-X instead of the much shorter times for 1:1 dilution and really liked the grain/contrast that I got. Obviously that is a personal taste thing related to each photographer, and it would not work for all images either. Skies would show too much grain using this scheme. Have fun w/ it, and keep careful notes.
     
  3. 1. As soon as any chemical comes into contact with the emulsion of the film a chemical reaction takes place. In development the silver hadies in the film are converted to silver solids proportionally to the amount of light that they were exposed to.
    2. As the chemical reaction occurs the developer in contact with the surface of the film exhausts out quickly. The chemical behind the front surface contact will affect the film but at a slower rate.
    3. Time and agitation increases both increase image density. Too much time will result in highlights that are too dense to print or scan.
    Time increase of 5% over starting point time is just perceivable.
    Time increase of 25% is considered a 1 stop push.
    Agitation increase from intermittent to continuous requires a 10% decrease in time in standard processors.
    4. Small shifts in development time and agitation affect tones and their separation.
    5. Development time shift range suggestion: 10% under to 15% over.
    6. Agitation suggestion: 5 seconds once each minute, 5 seconds every 30 seconds, 5 seconds every 15 seconds, 10 seconds each minute, 10 seconds each 30 seconds.
     
  4. Thank you, I'm looking forward to trying out these suggestions...
     
  5. James G. Dainis

    James G. Dainis Moderator

    It sounds like you are starting to delve into the Zone System.

    Read the first paragraph here to get a better understanding of what happens when you develop film:

    http://www.jdainis.com/zone.html
     
  6. Well, yes, I've been trying for some time, ;-) finally have the equipment together, and how to use it.
    Now its time to get into the developing nuances down . Took twelve images, all indenitical with the 'ole speed. Tomorrow morning will start developing them.
     
  7. As to agitation:
    The light sensitive salts of silver are imbedded in a binder made from unflavored gelatin. Gelatin is used because it is transparent, flexible, has low solubility in water, and it's permeable. When exposed film or photo paper is submerged in the developer, the solution, which is mainly water, causes the gelatin binder to swell. This opens up the structure allowing the developer to infuse. This action allows the developer to contact the silver salts.
    Silver salts are comprised of silver combined with a halogen (Swedish for salts maker). The three halogens used are iodide, chorine, and bromine. When exposed to only a negligible amount of light, silver halogen crystals are rendered developable. The developer amplifies the effect of the exposure as it has the ability distinguish crystals that have received only tiny amounts of exposure. It ignores crystals below a given threshold of exposure. Thus the developer is selective. The developer is a reducing agent. It liberates (splits) the exposed silver halogen into its two component parts. The liberated halogen component is soluble thus it is dissolved away by the waters of the developer. The liberated metallic silver is insoluble and thus remains imbedded in the gelatin. The now liberated metallic silver is opaque. This is the black & white image you see. The image is comprised of countless tiny flakes of silver. Unexposed silver halide crystals resist reduction by the developer and will be dissolved away by the fixer.
    Thus, the developer first infuses into the film or paper emulsion (gelatin + silver halogen) and reduces only exposed crystals. The halogen component that is liberated, if allowed to remain on site, acts to restrain additional development. We agitate to create currents in the fluid. These current stir and flow and thus flush out the halogen restrainer from its location and replaces it with fresh more energetic developer.
    Lack of agitation effect all areas of the developing image however; areas receiving high levels of exposure (highlights) are most affected. In highlight areas, most of the silver salts will have been rendered developable. The developer that has infuses into highlight areas quickly reduces and is exhausted. Unless flushed out and replaced by fresh more energetic developer, the amount of blackening in the highlight areas is suppressed. Lack of agitation in the shadow areas has far less impact. In areas of low exposure, the developer reduces fewer crystals thus it retains its strength for a far longer period. It can continue to work without agitation. The main effect of reduced agitation is lowered contrast, as the highlight will not be developing to their full potential.
    As to development time:
    The duration of development determines the degree of completion. Longer time in developer results in more silver being accumulated in areas of heavy exposure. These areas obtain maximum blacking (dmax). Longer time, allows areas of moderate exposure to also develop up to a higher density. Shadow areas having received little exposure will not gain much density due to reasonably prolonged time in the developer because they are will remain below the threshold necessary to cause them to be reduced (developed). The result is higher ISO speed, more contrast and sorry to report more graininess (silver flakes amass).
    Prolonged development time nullifies the development threshold of the silver halogen crystal. Thus it will be reduced even if has little or even no camera exposure. The result is overall elevation of density. We call this fog.
     
  8. Alan, I am familiar with the process, but your description gives to it a clarity, and completeness, that I have not come across before.
    Thank you...
    ~~~~~~~
    Update.. only got two images developed today.. D-76 and HC-110 done in my normal manner, to be a reference.
    Scanned them, (SliverFast) and did a crop detail, which showed the HC-110 had a slight bit more contrast than the D-76.
    BTW..
    Film is Efke 100..
    D-76 using 1:1 for 10 min, @ 68* - agitate first 30 secs, and then invert once every 30 sec there after.
    HC-110 solution H... for 11 min, which is 6 ml of HC-100 to 349 ml of water @ 68*
    (The home made, 2"ABS 'tank', holds 12oz, for one negative. Made two of them, several years ago, when got to shooting with the '46' 'orphan' Anniversary 3x4 speed )
    ** One thing I do not do, in the summer, and have been reading in the archives, that some stress having the stop, (in my case, tap water) fix and wash all at the same temp.
    Soooo... how many of you feel that this is critical?
     
  9. One gets their best results when all chemicals, developing tank, film, and wash water are within 1°F of one another. Easy to obtain and maintain in a 30 minute processing session.
    At a temperature variation of 2°F detectable processing artifacts can start to occur and get worse as the temperature variation increases.
    How tight I keep the temperatures depends on how critical I want the finished image to be but I don't let them get over 2°F.
     
  10. James G. Dainis

    James G. Dainis Moderator

    6 to 349 is a 1:58 ratio.

    I thought Dilution H was supposed to be a 1:63 ratio.
     
  11. yep.. bad dog no bone... ;-)
    Thanks .. reading achieves it stated you had to have a minimum of 6ml of HC-110.. so will mix it 372 ml of water instead of 349. It will be over 12oz, but so what!
     
  12. James G. Dainis

    James G. Dainis Moderator

    Peter, you are still 6ml of water light.

    6:378

    =

    1:63
     
  13. Ah... THANK YOU ... 6mil AND 378... of water.. not total of 378 with the 6 mil HC-110 included!
    This is a great forum.. for the help you get!
     
  14. One of the nice things about HC110 is that you can mix it as you wish and adjust development time accordingly as long as you use enough concentrate to fully develop the amount of film in the mixed solution.
    6ml of concentrate will develop 80 square inches of film.
    80 square inches of film = 1 sheet of 8x10, 4 sheets of 4x5, 1 roll of 120, 1 36 exp roll of 135, 5.79 sheets of 3 1/4 x 4 1/4, 10.9 sheets of 2 1/4 x 3 1/4 film.
     

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