Just a note on DDP. I tend to use it sparingly on luminance data, but I know others that use it as the primary means of stretching data. The process can deliver pleasing results, but for ultimate control, its hard to beat photoshop's levels and curves. The ability to display both shadows and highlights in a single process if not correctly understood can lead to trouble. Take note of the mid-level as this is where you tell the histogram to start the progressive curve to highlights.
Like all tools they have their place. I do like DDP for RGB data however. Stretching it as far as the colour data will permit, followed by heavy saturation, then introduce the layer as a softlight blend, then drop the opacity to taste. If that doesn't bring on the vibrant colours, duplicating the softlight layer again (two softlight blends) will surely get you rich colours. mmmm s a t u r a t e d c o l o u r ....
Jase - Thats an awesome technique right there.. I've been having some nightmare issues trying to get nice vibrant colours from HaRGB shots, the soften blend routine as you described above is going to get a test run tomorrow!
I too prefer levels and curves to DDP... I use DDP at times, but generally find levels and curves creates a better, more contrasty image..
Notwithstanding any great advice given so far but maybe
a 2 pic comparison to demonstrate 16bit histograms.
Pic 1 is a raw result of Eta Car with the histogram superimposed.
A huge amount of info is in that image.....it's all just crammed
right down the left hand end where I have arrowed.
Repeating what others have said, because you are working with
the 16bit complete range still, there is a lot of info you can tweak
and stretch with careful application of curves from this point on.....
that is...while it is still a full 16bit image.
Pic 2 is that info now stretched with a careful curve applied.
See how much was crammed down there.
Hope this helps. (btw my cam is slightly less than 16bit but the concept
still applies)
Thats some great stuff, and thats exactly what i get. i looked like an eejit, and i should have researched this alot more, before going down that route of CCD imaging, maybe a couple of years with the DSLR instead of 4 months, would have stood me in better stead, that said, if i can work out how you got from one image to the other, then i am off and running ... and i guess thats where the DPP stretch comes in.
Quote:
Originally Posted by kinetic
Duncan,
Notwithstanding any great advice given so far but maybe
a 2 pic comparison to demonstrate 16bit histograms.
Pic 1 is a raw result of Eta Car with the histogram superimposed.
A huge amount of info is in that image.....it's all just crammed
right down the left hand end where I have arrowed.
Repeating what others have said, because you are working with
the 16bit complete range still, there is a lot of info you can tweak
and stretch with careful application of curves from this point on.....
that is...while it is still a full 16bit image.
Pic 2 is that info now stretched with a careful curve applied.
See how much was crammed down there.
Hope this helps. (btw my cam is slightly less than 16bit but the concept
still applies)
that said, if i can work out how you got from one image to the other, then i am off and running ... and i guess thats where the DPP stretch comes in.
It's like riding a bike mate, once you 'get' it you won't forget it
Only thing is, people like Jase just ride their bikes so much better
than me and make me look hopeless ......and Alex, well he has
a new bike every week
It's like riding a bike mate, once you 'get' it you won't forget it
Only thing is, people like Jase just ride their bikes so much better
than me and make me look hopeless ......and Alex, well he has
a new bike every week
Steve
i will stack some images from the other night, and see what i can come up with
yeah mate, i am aware i am asking some really dumb questions, been observing since i was 11, but only imaging in the last few months.
i like to think it evens itself out, when i can help people with stuff i know about.
usually IT issues, or guitars !!
Hi! Sorry, they are not dumb questions! If you have to ask them, go ahead. I was trying to help you put a short cut in place and you can always refer back to it at any time.
He, he, that reminds me, I need to get some guitar strings for my daughters guitar!! Thanks!!
ok, so now we are getting somewhere! stacked some frames, no lights etc, just to see how this would look, i think it looks quite promising!!
all i need now is :
Some advice on the best DDP settings
and
When i save this image as a TIFF, and open it up in CS4 its all dark again, do i have to flatten the image or something? how do i get it looking like this, no matter what i open it in?
thanks!!
EDIT : i know its says the file is a PNG, i saved it in a few formats to see if anything would happen, but the file in question is a TIFF
Did you check auto for both background and mid level? This will provide you with the baseline settings for the image in question. Make sure there is no black boarders due to slight alignment errors or similar as these are also taken into account.
Once the above had been actioned, did you subtract 200 counts from the background? The screen stretch looks clipped, but in may not be if you zoom in. Move the red triangle (black point) all the way to the left or simply enter zero in the minimum field and hit enter. Then use the + magnifying glass to check if clipping has occurred.
I forgot to mention the DDP in MaximDL by default also sharpens your data as it stretches it. If you want to disable DDP sharpening enter the DDP dialogue box (see attachments below) and create a filter as shown. This will disable the sharpening function. Of course you may choose to keep sharpening enabled, but I prefer to use other tools for sharpening such as deconvolution, USM (unsharp mask) or HPF (highpass filter). If the image is noisy, you will certainly not want to sharpen as you stretch the data as this will simply exacerbate the noise.
Depends on how hard you've DDP stretched the data. Once you click OK, DDP is then applied. No form of imaging flatten etc required. Just save as a 16bit tiff and open in PS. Looking at the histogram on the screen stretch, I'd say you haven't applied it hard enough, but without having a good look at the data its hard to tell. On the screen stretch windows, when you move the green arrow to the left i.e decrease the white point, are there any black boarders around the image? You will want to crop these out for the best result.
Unfortunately, there is no one size fits all setting with DDP. You need to adjust it on a per image basis to get the desired result. Try stretching the data really hard and see what happens in PS. Backup your data and experiment - you've got nothing to lose!
