RickH wrote:
In shooting flowers, I'm struggling with getting accurate colours, especially with purples and reds. See the attached for instance. Additionally, these colours tend to blow out details. Any advice? I've tried to adjust in post processing
Rick, I took another look at the image and this is what I found.
Obviously you did not shoot this in sunlight.
You have over saturated blue and purple(magenta) channels.
Your image is not overexposed.
It can be adjusted in post processing.
Using a color checker passport and a raw file of this image is the best (fastest and most effective) way to fix this, though it can be handled as a 16 bit tiff, or even a jpeg file.
The only clipped highlights are some of the tiny bright spots (similar to specular highlights) on the petals of some of the flowers. The brightest I found were a couple at 250. This is something that using a threshold layer can mislead you on.
You need channel specific information to be able to fix this, and you need to be able to localize your adjustments to the specific color range and area on the image.
To show you channel clipping, add a Levels adjustment Layer, click on the white sampler eyedropper, hover over the image and press Alt key. This will show you the clipped channels.
The first image below is a screenshot of the clipped channel information.
The second is the expanded view of the histogram and as you can see, the exposure is as far as it can go without clipping.
The image just needs a little TLC. I did a little work on the jpg that you posted, but clearly a D800E can produce a stunning image with much more detail. If you shot this in raw, then there is even more recoverable information in those highly saturated blues and purples.
The third image is the result of using a saturation mask, making small adjustments to the blue and magenta channels for saturation and levels, and using the mask again to locally adjust local contrast - I used the unsharp mask filter with a large radius (I think I used 400) and a relatively small amount - about 18%, then went back and used a normal amount (around 200%) and a small radius - .7.
Using an original raw file I can get better results. There is an alternate method that uses channel mixing to copy the detail present in one channel to another, which is useful for moderately blown highlights. But I didn't try it on this image.
Let me know if this was what you were trying to do on this image.