Saturday, September 18, 2010

Art of Triptychs, Diptychs and Polytychs - Intuition Versus Intellect, Left Versus Right

Yin Yang Cityscape

A few years ago I started a small group on flickr called Art of Triptychs, Diptychs and Polytychs. The form fascinates me but I can't help wondering how some of the contributers to the  pool do such a superb artistic and aesthetic job of choosing their images.
I confess my own polytychs are not very artistic. I'm a pretty equal right brain/left brain type of guy. Unfortunately this doesn't mean I'm balanced, quite the opposite at one moment of time I am either one or the other not both.

A chimpanzee brain at the Science Museum LondonImage via Wikipedia

For me polytychs are particularly hard art form because as soon as I start to think about joining 2 or more images together the reasoning/logical side of my brain switches in blocking out any intuition and creativity.

Off And On

I don't have this problem with in camera double exposures. I either plan the 2 shots before I take the first one or I take the first shot and hold it in my mind until I find something that fits with the first shot as the second exposure. In either case when I'm photographing my brain is usually in creative mode. I have been practising doing double exposures for several years now so even the planning is subconscious.

Tuesday, September 14, 2010

Converting A Colour to A Black And White Image Utilizing Selective Colour Contrast Filtering

Sometimes you might want to convert a colour image to B&W. You have used the usual techniques like contrast and brightness curves and maybe even the channel mixer, you have dodged and burned but it still seems to have lost some of the details of the original colour image.  Thats pretty normal because some of the details in the original are because of changes in colour not changes in intensity.
Consider a portrait where a person has no fashion sense or maybe Scottish and is wearing a red and blue plaid shirt. If the blue is near the same intensity as the red the checker pattern will blend in when you convert to B&W. Well the quick answer is to use either the channel mixer or a selected colour filter when you do the conversion this would either selectivity darken the red or the blue. But wait although the plaid shirt looks OK the skin starts to look blotchy, not very flattering for a portrait..
The answer is rather simple you selectively blend 2 B&W versions of the image together. One version optimizes the plaid while the other optimizes the skin. If needed you could add more versions  to optimism additional parts of the image.

Original Colour Image
I am going to try to illustrate using a bad example, bad because the colour version from the MF film shot looks far better then the B&W. Note the bright red berries back-lite translucent in parts and the bright green yellow pallet of the background.
In this example I used the channel mixer to create 2 images plus a 3rd which is the luminance channel from the original colour image.

Left: Red Berries                         Centre: Green Background                              Right: luminance channel
The best (at least for this example) of all 3 images were combined together to give the final image. The berries in the left image was selectively combined with the centre image and finally the low contrast upper right corner was taken from the luminance channel.

Final B&W with selective contrast filtering

Sunday, September 12, 2010

Fun With B&W Film - How To Do HDR From A Single Scan

Fun With Scanning 30 Year Old B&W Film - Single Scan HDR
Right side is a special colour scan of a B&W negative, the middle is a normal scan plus some dodging and burning. The right-side is a HDR image obtained with the 48bit colour left-side image. The right side is scanned in 48 bit colours where the individual RGB channels are adjusted for gain, offset and gamma via the histograms utilizing the epson software prior to scanning in this case the green channel is normal exposure the red is -1.5 stops under exposed and the blue is +1.5 over exposed. After the scan the RGB channels can be manipulated as a colour image or separated into 3 monochrome channels. You can then  process as a colour image or alternatively as an HDR or with tone mapping software. Or as I mostly do you could keep it as a toned image or convert it back to B&W.

This being 30 years old Kodak Plus-X it does not have nearly the dynamic range of that of most fresh films such as tmax would have.
Fun With Scanning 30 Year Old B&W Film - Single Scan HDR
RGB channels are actually B&W tinted for visualization purposes only

The Ghost That Walks Beside Us
The Ghost That Walks Beside Us is a direct manipulation of a 3 channel B&W scan

Casa Loma Stables - The gold tones are because of the scan RGB gains of (1.5,0,-1.5) The reverse of the blue tint above.

Saturday, September 11, 2010

Fun With B&W Film - How To Get Duotone Straight From The Scanner

Fun With Scanning 30 Year Old B&W Film - Duotone Straight From The Scanner
Left side is scanned in 16 bit B&W mode. Then duotone tinted in Lightroom. The right side is scanned in 48 or 24 bit colours where the individual RGB channels are adjusted for gain, offset and gamma via the histograms utilizing the primitive epson software prior to scanning in this case to give the red tint. The above film is 30 years old Kodak Plus-X!
Note: French lavender pictured above is now grown in some peach orchards because they repel a moth that is a pest to the peaches.English Lavender has a far weaker scent and does not have any of the  same insect repelling properties.