Black And White Duplication Routes
Flashing Black and White Films
Black and white films pre-flash easily but are rarely used, as their contrast can be more easily controlled by development. Some camera negative film stocks are occasionally pre-flashed to achieve very low contrasts for use in exceptional circumstances.
Printing and duplication routes for producing Black and White reproductions
The diagram shows the main routes, and indicates where panchromatic films are used, especially in order to make a black and white reproduction from a colour film. This is essential in the case of tinted and toned films as well as natural colour films.
Optical blow-up and reduction can be carried out between 16mm and 35mm, or in order to magnify or reduce any other gauge to 16mm or 35mm. No other gauges are available as print stocks today.
The 2-Point Procedure For The Production Of A Black And White Duplicate Negative
Making the black and white interpositive [master positive]
- Step 1 Plot on graph paper the characteristic curve of the interpositive material to be used. This will probably be either Eastman Fine Grain Duplicating Positive film or Eastman Panchromatic Separation Film [see the printing route diagram above].
The contrast [gamma] at which the film will be processed will be selected from a time gamma curve previously prepared, probably 1.5, to fit the pre-selected contrast of the duplicate negative film.
- Step 2 Find a suitable test negative with a series if plain uniform areas large enough to measure on the available densitometer preferably using a 3mm aperture. This test negative could be a locally shot scene including a grey scale, a Kodak LAD negative, a BESTS or an SMPTE standard negative, or a process control strip. It should be on a similar material to the originals to be duplicated. If the original is a conventional black and white, a black and white negative is used.
Mark on the control strip or test negative the steps that correspond to the highest and the lowest densities you can read off the original work negatives.
- Step 3 Print the standard negative or control strip at a range of exposures on the printer to be used to make the interpositive.
- Step 4 Process the test printing to achieve the pre-selected gamma
- Step 5 Measure the "print through" densities on the interpositive and plot them onto the characteristic curve produced in 1 above.
- Step 6 Assess which exposure of the test negative falls entirely within the straight-line portion of the characteristic curve and if none do make a new set of exposures in order to place the full range of "print through" densities on the straight line.
If the lowest density step is on the curved toe then a higher exposure is needed, if the highest step is on the shoulder a lower exposure is needed.
Continue to test until the range falls on the straight line.
- Step 7 Expose the work at the defined exposure.
Some black and white interpositives are made using the grading exposures used in printing the original negative and result in a "graded interpositive" or "graded master" which, when printed to make a duplicate negative, can be printed at one printer light to achieve the original grading. This may not be practical with archive film.
Making the duplicate negative
- Step 1 Plot on graph paper the characteristic curve of the duplicate negative material to be used. This will probably be Eastman Fine Grain Panchromatic Duplication Negative Film [see the printing route diagram above]
The contrast [gamma] at which the film will be processed will be selected from a time gamma curve previously prepared, probably 0.65 - 0.70, to fit the pre-selected contrast of the duplicate negative film.
- Step 2 Find a suitable test interpositive with a series if plain uniform areas large enough to measure on the available densitometer preferably using a 3mm aperture. This test image could be the interpositive made above as the test for preparing interpositives, or a process control strip on the interpositive material.
Mark on the control strip or test negative the steps that correspond to the highest and the lowest densities you can read off the original work interpositive.
- Step 3 Print the standard interpositive or control strip at a range of exposures on the printer to be used to make the duplicate negative.
- Step 4 Process the test printing to achieve the pre-selected gamma
- Step 5 Measure the "print through" densities on the duplicate negative and plot them onto the characteristic curve produced in 1 above.
- Step 6 Assess which exposure of the test film falls entirely within the straight-line portion of the characteristic curve and if none do make a new set of exposures in order to place the full range of "print through" densities on the straight line. Make corrections as described above.
- Step 7 Expose the work at the defined exposure to make the final duplicate negative.
The resulting duplicate negative will need grading much as the original negative would have needed unless the interpositive was made with grading correction. Even if this is the case it is unlikely that an entire production will only need one printer light setting.
LAD For Black And White Duplicate Negative Production
Kodak has published values to enable the LAD method to be used on some black and white film stocks. The method used should be a form of the methods described in Ch 9, Grading, but measuring of the LAD step to Status V density.
- Original B/W negative [Kodak stocks] 0.65
- Eastman Fine Grain Duplicating Positive Film 0.75
- Eastman Fine Grain Duplicating Panchromatic Negative Film 0.75
2-Point Procedure For The Production Of A Black And White Internegative From A Positive
- Step 1 Plot on graph paper the characteristic curve of the internegative material to be used. This will probably be Eastman Fine Grain Duplicating Panchromatic Negative Film, whether the original is a black and white, or colour, a reversal original, a tinted, toned or stencilled print [see the printing route diagram above].
The contrast [gamma] at which the film will be processed will be selected from a time-gamma curve previously prepared, probably from 0.45-0.60. The gamma required will probably found by experiment and the following table is only a guide.
- Black and white release prints 0.40-0.65
- Black and white reversal originals 0.40-0.50
- Tinted and toned films for Desmetcolor 0.45-0.50
- Tinted and toned films for black and white prints 0.55-0.60
- Colour prints - neg /pos 0.50-0.55
- Colour Prints – Technicolor 0.40-0.45
- Kodachrome and early colour reversal 0.35-0.45
- Reversal colour news film 0.50-0.55
- Step 2 Find a suitable test with a series if plain uniform areas large enough to measure on the available densitometer preferably using a 3mm aperture. This test image could be a locally shot scene including a grey scale, a Kodak LAD print, a B.K.S.T.S or an SMITE standard print, or a process control strip. It should be on a similar material to the originals to be duplicated. If the original is a conventional black and white, a black and white print is used.
Mark on the control strip or test print the steps that correspond to the highest and the lowest densities you can read off the original work negatives.
- Step 3 Print the standard image or control strip at a range of exposures on the printer to be used to make the internegative.
- Step 4 Process the test printing to achieve the pre-selected gamma
- Step 5 Measure the "print through" densities on the internegative and plot them onto the characteristic curve produced in 1 above.
- Step 6 Assess which exposure of the test negative falls entirely within the straight-line portion of the characteristic curve and if none do make a new set of exposures in order to place the full range of "print through" densities on the straight line.
If the lowest density step is on the curved toe then a higher exposure is needed, if the highest step is on the shoulder a lower exposure is needed.
Continue to test until the range falls on the straight line.
- Step 7 Expose the work at the defined exposure.
Some internegatives are made using grading changes to printer lights judged to correct the original print [by sight grading], and the resulting internegative carries the corrections and can be printed at one printer light throughout. This may not be practical with archive film, but does reduce the effort of grading later.
Lad For Black And White Internegative Production
The Kodak published values to enable the LAD method to be used on some black and white film stocks can also be used to set values for a black and white internegative. The method used should be a form of the methods described in Ch 9, but measuring of the LAD step to Status V density.
Eastman Fine Grain Duplicating Panchromatic Negative Film 0.75