i have been trying to capture crowns, ejection towers and splashes with hi-speed photo techniques and had some success and much enjoyment. On my second session i caught a number of frames with the effect shown in the image attached, apparently instead of being absorbed in to the main body of water the drips formed beads that rolled or ran around the surface. I assumed this was a trick of surface tensions but have not been able to find anything like this thus far on the net. the droplets remain for many seconds, indeed looking through the number of frames taken the suggestion is several minutes. My set up includes ordinary tap water with food dye for colouring.

There does not appear to be any images that I can find demonstrating this phenomenon on the web, yet it is a very pleasing image. Curious.

Many thanks 

NN

Nicéphore Niépce’s photograph “View through a Window at Le Gras” of 1826 is said to have been made by coating a pewter plate with ‘bitumen of Judea’ and exposing it in a camera for at least eight hours.  The plate was then washed in a mixture of white petroleum and lavender oil, in order to remove the bitumen not ‘hardened’ by exposure to light.  

Niépce originally called the process ‘Physautotypie’, and later ‘Héliographie’ - although it seems not entirely clear whether the two names in fact refer to slightly different processes.

Contemporary experimenters seem to get good results with the following recipe:

Lavender oil is gently heated for several hours, until all the volatile compounds have evaporated and a hard, brittle resin remains. This is dissolved in alcohol and coated onto a glass plate. After exposure, the plate is exposed to white spirit / paint thinner fumes, until the image appears.  Violin rosin is sometimes used instead of the Lavender Resin.

The story of Niépce’s ‘first photograph’ is often told - but nowhere have I seen any indication of what chemical processes may be involved.

At what point in the process does the bitumen / plant resin become light sensitive, and especially: why?

Many thanks!

Simon from Switzerland

Nicéphore Niépce’s photograph “View through a Window at Grasse” of 1826 is said to have been made by coating a pewter plate with ‘bitumen of Judea’ and exposing it in a camera for at least eight hours.  The plate was then washed in a mixture of white petroleum and lavender oil, in order to remove the bitumen not ‘hardened’ by exposure to light.  

Niépce originally called the process ‘Physautotypie’, and later ‘Héliographie’ - although it seems not entirely clear whether the two names in fact refer to slightly different processes.

Contemporary experimenters seem to get good results with the following recipe:

Lavender oil is gently heated for several hours, until all the volatile compounds have evaporated and a hard, brittle resin remains. This is dissolved in alcohol and coated onto a glass plate. After exposure, the plate is exposed to white spirit / paint thinner fumes, until the image appears.  Violin rosin is sometimes used instead of the Lavender Resin.

The story of Niépce’s ‘first photograph’ is often told - but nowhere have I seen any indication of what chemical processes may be involved.

At what point in the process does the bitumen / plant resin become light sensitive, and especially: why?

Many thanks!

Simon from Switzerland

As an amateur photographer I'm familiar with the idea of light having a colour temperature and having to adjust a camera for white balance e.g. early morning light is much warmer than midday. I've read in books on photography that light before dawn is always colder than the light after sunset.  I would have expected it to be the same.  Why should the direction of the light affect its temperature? Is this just a UK phenomenon or is it worldwide ?