Home Internegging, Part II
Round Two
Round One demonstrated a common problem call contrast built-up in a
duplication process. The specialty interneg film or duplicating film are designed to
overcome this problem. A poor-man's alternative is commonly known as the
flashing, which can also overcomes this problem to some extend.
Flashing is done by double exposure. One of the exposure, referred to as the
normal exposure, exposes the film the same way as Round One. The other,
referred to as the flashing, exposes the film without the slide in place thus
the negative is evenly flashed. For instance, if the normal exposure gives a mid-tone
area a unit exposure, and the highlight area 4 units of exposure. The 4:1 ratio
essentially represents the contrast. With the flashing, both the mid-tone area and the
highlight area are additionally exposed for 0.5 unit, say. Then the ratio becomes 4.5 :
1.5. This effectively reduces the contrast.
Technical Information:
- Films: Fuji Super G+ 100. Again, a random choice.
- Exposure: Every frame is made by double-exposure. The normal
exposure compensation values are +2.3EV and +3.3EV. The flashing exposure
compensation values are -1, 0 and +1 EV. Thus, 6 negatives were made for each
slide. An 81A warm-up filter is used to see whether it is necessary to lower the color
temperature of the flash a little bit.
- Processing: This time, I didn't even bother to put any special mark
on the film processing order. Just regular 4"x6" machine prints. The same set of
scanning parameters were used without further modification.
Comparison:
It appears that the flashing has significantly reduces the contrast, but even the -1EV
compensation for flashing is over-flashed. In the following, only the print results with
-1EV flashing compensation and +3.3EV normal exposure compensation are
shown. Again, the left column are scanned from original slides, and the right column
are scanned from prints made in this round of trial.
Despite the distinctively
different color casts (partially due to the use of 81A amber-colored warm-up filter,
partially due to batch variation of machine printing) between the prints made from
interneg, and the original slides, the prints alone are actually very acceptable as
average quality machine prints. For example, the photo of the people in the snow
scene. I have another photo of me shown to the right, taken at the same time by a
friend using Olympus Infinity 2800 P&S camera and Fuji Super G+ 100 print film,
processed by the same Qualex lab. Basically, between this photo and the print made
from my home-internegging, there is no significant quality difference, in color,
contrast, sharpness, film grains, etc. Even the photo made from original print
film has the similar color cast! This similarity in the colorcast suggests that the 81A
filter is not the sole cause of the brownish photos.
Conclusion from Round Two:
- The flashing exposure has very prominent effects on reducing the
contrast. A compensation value of -1EV is probably the maximum that could be used.
This compensation value actually reduced the contrast even lower than the original
and yet produces acceptable results. Higher compensation values generate grayish
shadow areas.
- For the normal exposure part, results with +2.3EV compensation are generally
good, and with +3.3EV are slightly better. This suggests that a compensation of
+3.0EV is probably the right exposure. At least, very good with print films.
- The warm-up filter 81A is unnecessary. In fact, it may shift colors. (But, without
it, the colors in Round One seem a little bit cooler. Probably should use the filter only
with flashing exposure.)
- Need to further compare the effects of flashing exposure compensations
from -2 to -5EV.
Go on to Part III:
Round Three
Back to my Film Study Page
Last updated: July 1, 1997. 
