Longtime exposures hold a special appeal for me. Again and again I try do do it. I found the idea for this picture in a book about modern photography. The photographer took a picture of flowers in a vase with a specially built camera for many days until the first petals fell. The passing of time, which often cannot be experienced directly by us, can thus be illustrated by a photograph. Due to the new corona virus we had plenty of time at home to make flower photographs.
With my macro lens I can only realize the aperture value f/32, which means that even at ISO 50 the exposure time dose not rise above 15s possible when the lightbox is turned on. As an approximation to a true long-time exposure, I started a series of 23 HDR images at irregular intervals over the course of 4 days, just as it became apparent that my tulips would rise wide.
Each HDR image was created from6 shots at f/32 and ISO 50 with exposure times of 0.5s, 1s, 2s, 4s, 8s and 15s. The biggest difficulty was to block off a part of our living room before Christmas so that the exposures could always be done in the same way. Furthermore, the camera was not allowed to be changed by switching it on and off, changing the exposure times or removing the memory card.
I processed the layer stack of 23 TIF images in two ways. First straightforward as a smart object and then change the stacking mode in Photoshop as an average. Or fade out the layers after the start shot using black layer masks and gradually paint in interesting parts of the later images with a soft brush to create an overall impression. This approach was more promising to me than averaging the layer stack, which in my eyes expresses the flow of time too weakly.
Just to do the math: each image of my camera has 151 million pixels with a file size between 125 and 180 MByte in RAW format and 866 MByte after a RAW conversion to a TIF file. The total size of the project is something above 300 GB. 138 RAW files sum up to nearly 21 Billion Pixels. The final image has 159 million pixels due to some added background at the top of the result.