brainstorms

Monday October 25, 2004

carl. monkeys, perls.

a good friend forwarded carl malamud's interesting response to esr the other day. for whatever neuronal reason, it reminded me of that famous note by erik naggum on perl.

not sure what the connection is.

(2004-10-25 18:50:55.0) Permalink

montages in a digital darkroom

slide montage (sometimes called a slide sandwich) is a technique some photographers use to create impressionistic, often surreal images[1]. montages are done with two or three over-exposed slides of either the same subject, or different subjects mounted together in various ways. as the slides overlap, some colors saturate, some over-exposed details disappear and other details come together to create a three-dimensional feel; the result is what andre' gallant calls a dreamscape[1] image.

the trouble with slide montages is that you have to make your images with montages in mind; for an ethereal single-image montage, you may over-expose two slides one or two stops, keep one of the slides sharp, and defocus the second slide [2]. some photographers who do a lot of montages over-expose a roll or two of textures that may work well with other subjects. other photographers resort to using some of the accidentally over-exposed slides in montages to create unexpected lost-and-found images. [do not ever discard those over-exposed slides]

in the digital darkroom, montages are much easier, even if missing the choice and judgement of photographing in the field. we can re-create a version of the montage we missed from a single image. the idea is to simply generate the equivalent of those two slides from a single properly exposed image. in this example, we start with a promising image, something like this detail from st james cathedral in toronto. [oz/2004][3]

it seems easy to create an overexposed version of the original image, but it helps to know something about the way a good slide film (eg. velvia, provia) responds to over-exposure. simple change in brightness will make the image too flat for a good montage. in this example, the first montage image is a curve adjusted version of the original, imitating velvia with about 1 2/3 stops overexposure. [i really should do a comparison of an overexposed slide with an imaginary version to document the color changes]

the second image is a copy of the first image, but it has less over-exposure (about 1 stop) and heavily blurred. blur is the important part: if you were doing this blur with your lens in the field, there would be a change in the image magnification. this depends on the lens and the level of blurring (usually works best with long lenses) but it is this magnification change that produces the ethereal effect often seen in these montages; the second image is larger, so everything appears with a ghostly shadow/halo around it. in order to have the same effect, we slightly enlarge the blurred image. what kind of enlargement will work better in the final montage may require some experimentation.

the last step is to combine the two images (layers if you like) with the appropriate level of opacity [i used 80% in this example, ymmv] and multiply.

save, print.

when i made the original image a couple of months ago, i was working under light rain and with a digital camera (and no body with slide film), so i did not think of making any montage images. now i have the montage i missed that day, and i feel that it is a fine addition to my portfolio [4].

Notes:

[1] for discussion and examples of montages, see andre's book or his galleries or freeman and andre's photo impressionism and the subjective image.
[2] the type of single-image montage discussed here seems to have been made popular by the vancouver photographer michael orton, so sometimes it is called the orton technique. see his book for more montages.
[3] Nikon D70 with 28-105mm f/3.5-4.5D, set at 80mm, 1/30 sec F/5.6 handheld.
[4] very limited (max 16) professional prints of my images on epson matte archival paper or somerset velvet are available.