Exposure & Developer Test, Cranberries

X-​Ray Film Exposure Test (Cranberries)

Update

This arti­cle was updated on to include links to x-​ray film online retail­ers.

Cranberries Tone Curve
Cranberries Tone Curve

This is a series of shots I made to work out the expo­sure char­ac­ter­is­tics of Kodak Ektascan B/​RA film. Ektascan is an orthochro­matic x-​ray film sold in 8″×10″ sheets and larger. I cut it down to 4″×5″ for use in my Wista 45DX wooden field cam­era kit­ted with a Schneider Symmar-​S 5,6/150 lens. I used a yellow-​green (X0) fil­ter but made no allowance for a fil­ter fac­tor, bel­lows draw, or reci­procity.

The 1st image is an unal­tered scanBecause the scan is of a neg­a­tive trans­parency, I inverted the curves to yield a pos­i­tive image. I made on a very old consumer-​level flatbed scan­ner. The 2nd image was made by adjust­ing the curves in Adobe Lightroom® 5 for higher con­trast. Because the film has a blue poly­ester base, whites appear as light grey to the scan­ner, so 1 of the adjust­ments involved reset­ting the white point in the curves. In the U.S., x-​ray film may be pur­chased from Amazon, the Film Photography Project, ZZ Medical, or CXS Online.

Exposure & Developer Test, Cranberries
Exposure & Developer Test, Cranberries — Unretouched Scan
Exposure & Developer Test, Cranberries
Exposure & Developer Test, Cranberries — Adjusted Curves

Light Meter Readings

The scene was illu­mi­nated by nat­ural light from a win­dow under cloudy con­di­tions in the early after­noon. My reflected read­ing was .7 sec­onds for ƒ/5.6 at ISO 80. Incident read­ing was 6 sec­onds for ƒ/5.6 at ISO 80. This works out to:

  • Reflected
    • 1 sec­ond at ISO 25
    • ½ sec­ond at ISO 50
  • Incident
    • 6 sec­onds at ISO 80
    • 3 sec­onds at ISO 160

Starting from the left to right and top to bot­tom, the expo­sures were made at ½, 1, 3, and 6 sec­onds at ƒ/5.6.

Darkroom

I devel­oped the film under a 7-​watt red safe-​light 1 sheet at a time to avoid scratches(x-ray film emul­sion is very soft, so the “shuf­fle” method is inad­vis­able).Most x-​ray film has emul­sion on both sides, which makes it even more prone to scratches. I employed tray devel­op­ment to allow visual inspec­tion while pro­cess­ing. Negatives #2, #3, and #4 were devel­oped in 66½° F. (19.17° C.) Pyrocat HD diluted 1:1:200. Negative #2’s devel­oper was just below 65° F. (18.33° C.); it was processed the next day when the ambi­ent tem­per­a­ture was cooler.

I soaked each neg­a­tive for 5 min­utes in plain water, then employed semi-​stand devel­op­ment. Except for neg­a­tive #1, I devel­oped for 15 min­utes, with an ini­tial “brush” agi­ta­tion using a 3″ “Hake” brush. I brushed gen­tly north to south and back for a total of 5 times in each direc­tion, waited 5 – 10 sec­onds, and repeated for a total of 25 agi­ta­tions per direc­tion dur­ing the 1st 2 min­utes in the devel­oper. At the 7½ minute mark, I brushed 5 more times (5 north and 5 south).

After 15 min­utes total devel­op­ment, I trans­ferred the neg­a­tive to a plain water stop bath. I fixed for 8 min­utes with Kodak Kodafix, turn­ing on the room light halfway through, then washed in cold run­ning water for 5 min­utes. I used a drop of Form-​a-​Flo wash­ing agent dur­ing the final rinse and then hung the neg­a­tive to dry.

I dis­posed of the devel­oper after each neg­a­tive and started with fresh “soup” for each new neg­a­tive. Because neg­a­tive #1 was badly under­ex­posed, I repeated the 5 north-​5 south agi­ta­tion at 15 min­utes and again at 22½ min­utes. I left the neg­a­tive in the Pyrocat for 37½ min­utes more, with no fur­ther agi­ta­tion (total time 60 min­utes). This even­tu­ally brought out the shad­ows and revealed the high­lights, but at the expense of a very low con­trast image. Negative #3 is, mys­te­ri­ously, darker than neg­a­tive #2, even though it was exposed for a shorter inter­val and processed exactly like #3 and #4. It also exhibits uneven devel­op­ment and mot­tling.

Scratches are vis­i­ble on all of the neg­a­tives, but com­pared to my 1st attempt using the “shuf­fle” method, they are minor.

Darkroom Equipment and Chemicals

I used the fol­low­ing equip­ment and chem­i­cals:

I did not use a clear­ing agent, although I have some Kodak Hypo-​Clear; it doesn’t seem worth the bother, espe­cially for wash­ing film — if I were mak­ing prints, that would be a dif­fer­ent mat­ter.

— Chris J. Zähller

About Chris J. Zähller

International Man of Mystery. Cocktail Nerd. Occasionally designs websites. Sometimes snaps a picture or two.

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