Preparing astro images for printing - tips and tricks

[xthestreams (Paul)]

Two and a bit years into the hobby (and a move from Bortle 9 to Bortle 1 later) I am finally summoning the courage to print what will probably be the most expensive photo I've ever taken - my first! (I keep telling myself the good news is that each image becomes exponentially less as I print more)

Following Andy's suggestion I took a look at print2metal.com, but I have to admit I am terrified of looking like a total idiot (maybe revealing is a better word) and that I don't know what I am doing.

So my question to the forum is simply, what are the tips and tricks for getting an image ready to print?
- how black should the blacks be?
- do I REALLY need a colour calibrated monitor? (can this hobby get any more expensive?)
- what's the "optimal" size vs. DPI combination when aiming for larger format prints?
- Officeworks vs. specialists vs. DIY with a decent home printer?
- substrates - pros and cons

Any pointers greatly appreciated, I've read some of the older threads so have some sense of direction - but given it's been 7 years since the topic has been discussed at any length, I thought it might also be worth getting a more up-to-date take.

Thanks in advance!

[mura_gadi (Steve)]

You can do a cheap colour calibration using your windows drivers, if you have control over the gamma settings. There are 3rd party apps and if you own a dedicated video card you'll have settings there as well. Gamma controls your RGB, its not a colour calibrated monitor but a lot cheaper.

Print the photo in a small page at a lower and lower rez. try 200dpi 1st, that will let you judge how low rez you want to go. Then its DPI x camera rez for how many inches per side you can expand too (4000x3000pixels = 20"x15" at 200dpi).

[Startrek (Martin)]

I’ve used Officeworks a few times ( 18 x 13 ) but not happy with colour and of course you loose resolution
You need to spend money on quality calibrated prints
My nephew is a professional photographer so he’s my next option

[Craig_]

One of the most important aspects of monitor calibration when it comes to printing is IMO not the colours, although this is of course important, but brightness. Most people have their monitor brightness cranked way too high, and prints on a medium without that glorious backlight illumination end up looking incredibly dim. I print a lot, although mostly landscape stuff rather than astro, and I keep my monitor at 100 cd/m2. Even then I generally need to bump the brightness a bit for the final print.

Size vs DPI depends on your medium (paper, metal, canvas) as well as viewing distance. If you see yourself sticking your nose up to the print a lot to take in fine details you will need higher native resolution than if you are generally viewing from further back. 300 DPI native (before resizing) is ideal but hard to achieve for a print of any reasonable size. I have printed onto paper stock at 200-ish DPI with great results. Canvas can tolerate even less. Use resizing software to upscale to your desired output size for a better result, and adjust your sharpening accordingly.

I use specialists to print. All depends on budget though. One trick I've found helpful in the past if you're unsure about resolution / DPI is to do a 100% crop from your desired print size and do a cheap print at Big W / OW to check it out. By this I mean let's say you wanted to make a 24" wide print at 200 DPI. To check you're happy with the final resolution and sharpnening, crop a 6x4" chunk at 100% out of that 24" and get a cheap Big W print done. You'll easily know if the file is going to deliver the detail you want or if you need to revisit your resizing / sharpening or desired output size.

[xthestreams (Paul)]

Thanks so far everyone, great suggestions and experience share. I had one print done and as mentioned, the background was inky black compared to the source image,too much so, I’ll try your suggestion of a full res crop.

I’m looking forward to learning more, cannot wait to get a few prints up.

[floyd_2 (Dean)]

Originally Posted by Craig_

Use resizing software to upscale to your desired output size for a better result, and adjust your sharpening accordingly.

That's definitely worth a shot. Certainly enlarging a shot will reduce the DPI, which in turn tends towards reducing final printable detail. Why don't you grab the demo of Topaz Gigapixel AI and see if you can push the DPI of your final crop / enlargement for better results?