Previous Entry Share Next Entry
calculating effective printer resolution...
Typing this "out loud" as I calculate numbers.. I found some 1939 Ames Arial photographs.. downloaded them all. Ends up being about 3000x3 by 3000x4 ... 9000x12000; possibly less, at full detail (1m pixels). Rather than try to fiddle with laser printing them.. i decided to try Wal-Mart's 20-cents-per-4x6 print deal.

But, to figure out what size to break things out so that the pixels are preserved, while being as small as possible, I first printed out a test pattern (from, supposedly). The pattern was 1500x1000 printed on a 4x6, and in the resulting print, the hash for 1x1 was not discernable, the hash for 2x2 had moire, and 3x3 had no visible degredation. So, if I go with the effective printer resolution indicated by the 2x2 hash, what sizes do I need to break the source pictures (each 3000x3000) into? including a bit of overlap? And how large will the final print be?

1500 -> 6" ~= 250 ppi -- that's what the walmart printer had to draw. if the walmart printer was exactly 250ppi, it would have come out perfectly; but it didn't; instead, the equivalent of 125 ppi had a little moire going. So, i'd make a guess that it was doing 150ppi or 200ppi instead.

So, if I went with 200ppi, that means a 4x6 print would hold 800x1200 pixels on it. Each 3000x3000 would get split into 3.75x2.5 pictures. Move that up to 4 x 3 pictures.. then I get 3000/x = 1000x750 for each picture, with a bit of overlap (ie, each picture would actually be 1200x800, but share some edge stuff)

<- 1200 -> <- 1200 -> <- 1200 -> ~= 3600 across; so the overlap in the middle is 300 pixels, so picture #2 would start at 1200-300 = 900 pixels in, and picture 3 would start at 2400-600=1800 pixels in.

<-- 800 --> x4 = 3200 = 200 pixel overlap, /4 = 50 , so the starting points are 0, 750, 1500, 2250.

And the grand total if I did everything will be: 9000/200 = 45" by 60" when its all said and done; at 112 pictures at 20 cents each is $22.50.

Hrrrm. I guess i'll start small .. i'll just do one of the 3000x3000 things, the one that has campus on it, and see how that turns out. The next time I play, anyway. And if it turns out that its actually 150 dpi and I loose some of the detail during the printing, then, well, i'll have to deal with that. :]

Pretty lightning outside. Laptop = disconnected,wireless,Rocks. Other quick news:

Music: I'm participating in a music thing on Friday .. another Cafe Unite, run by Scott. I have no idea what we're playing, just going to bring the guitar and see what happens.. i'll practise up a song on wednesday night, something with the words for Historic Old Towne in it. Its a fundraiser for one of their playgrounds. Unrelated, this morning's music practise session went pretty well. Jim has an amazing voice.. doing Amazing Grace to the tune of HouseOfRisingSun, and Charlene and I listened to Time and a Word.

TKD: Still lovin' it. I get to revisit Master Pak's class tomorrow, and see how much i've improved. (Last time was an emotional meltdown for me; in December.) *going to be fun!*... my cardio is a lot improved now, and i'm just going to show up and see what happens. Also, while goofing off, i speed-punch-broke a rebreakable board. (toss in air, punch it and break it.) I sparred Alec today -- he's the blackbelt with the most sparring expertise. I had headgear on for the first time today, and I totally am *not* watching out for head shots, he got me with a couple. Must practise getting out of way and blocking high.

Health: Knee/calves started going funky tonight, seeing chiro tomorrow morning. All in all, healing well. 182 lbs, and somebody told me "the Fat is Melting off you Sunny" -- which is cool. I discovered a secret to pushups and situps -- BREATHE. I don't have to hold my breath as I'm engaging the muscles, I can do both at the same time, and its a LOT easier.

Misc: This afternoon, I pulled out a chair and napped in the sun. It was wonderful, warm weather, if a bit windy. And Yesterday, I fixed my garage door, it had, uh, come apart a bit.

Pissed off: While jogging on Friday.. i jog really slow, like an old guy with bad knees. Some punk pulled up next to me, leaned out of the car, and yelled "Are you jogging?" .. and drove off in a hurry. I was frickin PISSED. I wanted to smash his head apart, and realized that now, I could, I have some tools in that area. It was a bit scary. After detoxing with some friends, i did a lot better. It helps to have the affirmation that even if I jog slow.. its *working* for me, and that's the important thing -- what I get out of it, not what other people think I look like. As far as smart retorts go.. i can't think of any. I guess, i pity the fellow; he must really be hurting inside to want to ridicule me.

That's about it. Going to post to dailyexercise, and then go to sleep. Ciao.


Log in

No account? Create an account