Sunday, December 14, 2008

My First Really Big Print.

So I decided to try making a Really Big Print today. (It's working already - the printer was sitting there silently laying a guilt trip on me.) I asked my wife if she thought my father-in-law would like a poster print of his race car for his garage, and she said yes. So I intrepidly set out to make one.

I was going to do this picture:

But my wife liked this one better:

since you can see him racing other cars, and you can see his face. Okay, good enough.

Since I had already spent considerable time retouching that image, I didn't have to do a lot with it. I cropped it to the right aspect ratio (16x20 is 4:5, whereas my camera shoots at 2:3.) 4:5 is the same aspect ratio as 8x10, so I printed an 8x10 test print and examined it to make sure I was satisfied with the contrast, exposure, etc.

Then I upsampled it with Photoshop's Bicubic Smoother algorithm so that it was a 360PPI file. (This increased it from roughly 18MB to roughly 120MB in size.) Finally, I applied a sharpening filter that was appropriate for its new PPI and a print file.

Then I printed it using the appropriate print settings: in my workflow, I use Photoshop's color profiling rather than the printer driver's. I had a custom profile from the people who make the paper, so I just had to select that along with "Photoshop manages colors" in the Photoshop print dialog, along with of course doing a "Page Setup" and setting the proper orientation and paper size. (17x22, the size of four sheets of standard letter paper put together.) Then in the OS print dialog, I made sure to select the right paper type, the right color management (i.e. none - color management OFF) and the right print settings.

After going to the Summary tab to review the settings, I just hit "Print." It took about two minutes to render the print file. and then the printer lit up and the file started to spool. I popped the top of the printer to look and make sure the image looked to be fairly centered on the paper and nothing weird was going on - after about an inch of print it looked good and I shut the top and waited for the print to come out.

After another two minutes printed area started to emerge (this printer is BIG and it takes a while for the printed area to be visible outside the enclosure.) Then it was just a matter of watching it come out.


I can't show you - obviously it makes no sense to try to show the quality of huge printouts on a screen. But this looks fabulous. When you consider the lens I had (17-85mm IS, shot at 1/100s, f6.3 at 85mm) and what I was taking pictures of (race cars twenty feet away going forty miles an hour) it's ridiculously clear. You can read print on the car that is less than an inch high. You can see the tread cuts on the tires. You can clearly see, through his visor, that my father-in-law wears glasses. I was at max ISO (1600) and it's not even that noisy. (Some of that of course is post.)

So I'm pretty pleased with it. I went and bought a poster frame at Michael's (they were on sale pretty cheap) which I'll put it in tomorrow. I could probably put it in safely now, but I like to let prints outgas for a day or so before I put them behind glass or plastic. If I were going for maximum life/value, I'd mat it and put it in an actual frame, but this is just an acrylic frame. Since the print only cost me about eight bucks to make and it's going in a garage, it'll be fine. If I had paid forty or fifty bucks for it from a commercial printer, I probably couldn't be so blase about it. :)



Elessa said...

noise! that is the word i was looking for earlier today when i was talking to someone about cameras and ISO.

sooooo, what are you going to print next?

MarcWPhoto said...

I think I'll make a nice print of one of the baby pictures I took for my co-worker for her for Christmas. Her husband is going to go through them and pick one out for her so it will be a surprise.

"Noise" is the digital equivalent of "grain" in film.

Grain in film is caused by the "grains" of light-sensitive material (usually crystals of a silver salt) on the film. The bigger they are, the more likely they are to get hit by individual photons, which makes the film more sensitive to light. So if you want film that works in lower light conditions, you make the grains bigger. But as the grains are enlarged, they become more individually visible and you get more "orphan" grains showing up as darker or oddly colored specks on otherwise lighter or differently colored areas of exposure.

Obviously, the photoreceptor sites on a digital sensor never change size, but as the "ISO equivalence" of the sensor is increased, what is happening, metaphorically, is that each site becomes more sensitive to light. On average, that makes the sensor more sensitive, which is the idea, but it increases the likelihood that any given site will report being struck by a photon, even when the ones around it aren't being struck by similar photons, which produces your odd dark or strangely colored dots, referred to as "noise."

In both the case of film and light sensors, what's really going on is a lot more complex, but this gives you the flavor of it.