Printing / Accurate Colorization / Photoshop

The inherent problem is contrast. A good modern, monitor might have a contrast range of 1,000:1 or higher–sometimes much higher. Most photographic papers are closer to 70:1 with decent ink, perhaps 100:1 in the best pigment based printers on whitened papers. That means when you print, either you are losing details in the highlights or in the shadows. It's the same problem you had in processing the image in the first place, only now you have to go 10x farther in your stretching than you had to with your screen processing.

There isn't really a perfect solution, but there are steps you can take:

1) Make sure in Photoshop or Lightroom you are using a color managed workflow. I know you said you are already doing that. That's the baseline.
2) Make sure you are soft proofing the image when you make your adjustments for printing. I tend to save two versions of each image–the one that looks good on the screen and the one that looks good when printed
3) Don't be afraid to brighten shadows significantly for printing (even though the result will look bland on the screen). Otherwise, those shadows and faint areas of nebulosity will all go to mud.
4) Don't let the printer manage the colors unless you are OK with a bunch of trial and error. Instead, manage the colors in Photoshop and turn color management off in the printer
5) Depending on the brand of your printer, they all have strengths and weaknesses in terms of color saturation and gamut. I have never, ever gotten satisfying reds out of Epson printers, but, by contrast, I struggle to get the blues the way I want with Canon. Your experience may be different–it will also depend on the specific inks, papers, and paper profiles. Overall, I prefer what I get out of Canon printers since red is so important in astrophotography.
6) One you raise the shadows, you may need to make contrast adjustments. That may result in your losing some saturation in brighter areas. Don't be afraid to pump up the saturation a bit even at the risk of increased noise. Doing this in LAB mode will not raise noise as badly. Often this yields a really bad result on the screen, but a good result when printed.
7) Use the right paper profile–one made for that exact paper. It will increase accuracy. When you start pumping up saturation, that becomes a necessity.
Note that most printer gamuts are quite narrow. There may be colors that you just can't reproduce, and you run the risk of posterization and noise if you go too far with the saturation in an effort to force the printer to do what you want. Sometimes it just won't.
9) Start with a test print on a small sheet of paper, then, as you become happy with the result, increase size. This controls cost and ink usage. With terrestrial photography, I rarely have to resort to a test print, but with astrophotography (which is, almost by definition, HDR) it is nearly a necessity.

Good Luck!

- Jared

Jay,

I write in some trepidation since I am not an expert in colour, contrast, printing - nor that experienced in astrophotography yet (1.5years in).

But have found myself involved in local astrophotography exhibitions (mostly landscape AP, but some DSO work) this coming winter to support NZ's new national holiday of Matariki.

Many of the professional photographers exhibiting now choose to print on metal (Chromaluxe) to achieve much better contrast than paper for their AP compositions.  

It's expensive and specialised, but it has the additional advantage that you can hang the print directly on the wall without framing costs.  

Indeed, for the size of an A4 or A3 print (the size you could print off at home), the price is not that much different once the mount/frame is taken into account.

While my photography does pale in comparison to others, I have also printed some of my images off - and they do really "pop" this way.  

Brian

Brian & Wolfgang  –  Thank you both.  As I move forward in my experience(s) and meld the suggestions and advice of others, my prints are (and will hopefully continue) getting better.  Again, thanks to all, Jay

Brian Boyle:
Jay,

I write in some trepidation since I am not an expert in colour, contrast, printing - nor that experienced in astrophotography yet (1.5years in).

But have found myself involved in local astrophotography exhibitions (mostly landscape AP, but some DSO work) this coming winter to support NZ's new national holiday of Matariki.

Many of the professional photographers exhibiting now choose to print on metal (Chromaluxe) to achieve much better contrast than paper for their AP compositions.  

It's expensive and specialised, but it has the additional advantage that you can hang the print directly on the wall without framing costs.  

Indeed, for the size of an A4 or A3 print (the size you could print off at home), the price is not that much different once the mount/frame is taken into account.

While my photography does pale in comparison to others, I have also printed some of my images off - and they do really "pop" this way.  

Brian

@Brian Boyle ,

I am glad you mentioned metal prints.  I did a couple rounds of printing of some of my photos last year on metal prints.  The base I chose was with a bright white, rather than the natural aluminum base.  I have gotten good results, but it can still be quite tricky.  When I got my first prints, they seemed a bit dark.  I was able to have them redone, and for the new ones I generated data that were much brighter and contrasty.  These came back more acceptable, yet much darker than what my screen represented.  So the adjustments helped.  But here is the catch, these prints, even the dark ones, can look very different depending on how you display them.  In particular, the quality and intensity of the light illuminating the prints really makes a huge difference.  I think more so than for paper prints.  As my prints are mounted on a wall near windows, the presence of bright indirect light really improves their look.  And when the sun hits, they really pop.  I suspect if I were to illuminate with bright white (gallery style) lights, they would be consistently wonderful.  So be prepared to be disappointed on cloudy days and thrilled on sunny days!

I get the impression that the density of the inks applied onto a metal print may be greater than used for paper prints.  I have no evidence for this, but the light effect seems greater on metal print.  It may be that the base of the metal print is more efficient at reflecting light that passes through the pigments.  I am going to guess that the pigments physically sit on top of the base (white or aluminum) rather than penetrate the white substrate, as seems to be the case in paper.  But for your eye to see the image, light has to pass through the pigments once to get to the backing, then back out again.  Of course, some of the light may also get reflected back to the eye from internal reflections within just the pigment layer.  So if the metal backing does not commingle with the pigments, then it can act more as an efficient reflector.  Just speculation on my part.  There is also printing onto plexiglass.  And with that, you can imagine a back illumination that could be wonderful if done correctly!

Anyway, I think the above lesson learned is, even though issues of calibration, color, hues, etc. are resolved, the lighting used to display the prints cannot be ignored and can be just as important.  So when you evaluate whatever means that you use to print, try to be consistent also with the setting the prints will be displayed when evaluating the printing calibration.  Lighting color and intensity being key.  Maybe someone else will add even more detail on this aspect of print viewing.

I wonder how well home ink jet printers can print on paper under any circumstances.  So many astrophotos contain very deep blacks, in addition to deep colors for those that heavily saturate their images.  This is atypical of terrestrial images.  It is not easy for even the finest photopapers to absorb that much black ink, or colors for heavy saturation areas, without some bleeding.  This can affect apparent contrast and detail resolution.  The professional methods typically deal with that using dye transfer processes that can achieve these goals.  I think this speaks to limitations that @Jared Willson was highlighting.

The other thing, which is a bit off-topic in your question is print size.  I have seen a good number of prints done that are just too large for the intended viewing distance.  Some of these would have been great images if it weren't the fact that when viewed from a natural distance for the room, they looked blurred because the blown up image could not be sustained.  It impacts the apparent contrast and apparent sharpness of the details.  Fine for standing at the back of a room, but...

Also, TVs are now getting pretty cheap and have no bezels.  One could mount a TV in a frame and display it like a photo!  My TV actually reads USB thumb drives, so you could make the photo be fixed or scroll through multiple photos!

Alan