Does anyone know anything about Image Interpolation?

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I need to get an image printed. It's around 3MB, 180 dpi (this is the res they come off my camera at) and roughly 18 inches by 13 inches or 3200 pixels x 2400 pixels.

I need it to be 300dpi and 20x24 inches.

Is it simply a matter of changing the dpi and the dimensions. I realise there will be some loss of quality, but surely it won't break up too much?

Can anybody help?

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:00 (twenty years ago)

Are you paying money to have this printed?

― Jimmy Mod wants you to tighten the strings on your corset (The Famous Jimmy Mod), Sunday, 23 October 2005 23:09 (twenty years ago)

Yup, but only at my university.

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:10 (twenty years ago)

It's for my final piece of assessment for my degree.

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:10 (twenty years ago)

Welllllll the difference between 13X18 and 20X24 is much less than the difference between, say 5x7 and 20x24... so it should just be a matter of making the image bigger in PS. yes, it will block up some, but it might be acceptable. It's a trial and error thing, as far as I'm concerned....

― Jimmy Mod wants you to tighten the strings on your corset (The Famous Jimmy Mod), Sunday, 23 October 2005 23:13 (twenty years ago)

That's about a fivefold increase in file size. It really depends on the quality of the original (is it in very sharp focus?), and how compressed it was when it was first saved. If it was heavily compressed when it was first saved, the JPEG artifacts will really show up when the image is blown up. If it's sharp to start with (and the photos of your that you post on ILX generally are) it might be okay.

― I do feel guilty for getting any perverse amusement out of it (Rock Hardy), Sunday, 23 October 2005 23:14 (twenty years ago)

Also, this is useful:

http://www.americaswonderlands.com/digital_photo_interpolation.htm

― Jimmy Mod wants you to tighten the strings on your corset (The Famous Jimmy Mod), Sunday, 23 October 2005 23:16 (twenty years ago)

I haven't compressed it at all. In fact the images are still on my memory card as well as saved on my PC, so they're quite untouched.

I read something about programs specifically designed for Interpolation that kind of intuitively try to cope with digital image enlargement. Anyone know what I'm talking about or did I imagine it?

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:19 (twenty years ago)

Ooooo thanks Jimmy, that might be handy.

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:19 (twenty years ago)

I just tried straight up changing the DPI and the dimensions and it doesn't look too broken up at all. Yay!

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:25 (twenty years ago)

Even if you havent compressed it tho, if the camera saves it as a jpg then it will already have some lossy artefacting in it, and this may very well show up on a final print at a larger size.

Not a lot you can do about that... if the camera does RAW or TIFF format thats probably better to use for high quality printing. Verrry large files tho - my old camera did uncompressed TIFF at around 9Mb per pic.

― Trayce (trayce), Sunday, 23 October 2005 23:31 (twenty years ago)

(and it was only a 3mpx camera)

― Trayce (trayce), Sunday, 23 October 2005 23:31 (twenty years ago)

It does raw, I wouldn't have bought it if it didn't, but given the amount of photos I needed to take, I just opted for the highest jpg setting.

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:32 (twenty years ago)

Yeah that makes sense, I do the same otherwise its like, 2 photos and yr card is full! :/

― Trayce (trayce), Sunday, 23 October 2005 23:37 (twenty years ago)

Exactly. Even with a 1 gig card, sometimes shooting in RAW can be very slow, and under the conditions I was shooting, I needed to get things done quickly. Plus theres nothing more frustrating for a model than to have me fiddling frustratedly with my camera while they stand there under hot tungsten lights.

― Bombed Out and Depleted / Kate (papa november), Sunday, 23 October 2005 23:40 (twenty years ago)

Actual Pixels:

http://static.flickr.com/31/55393574_8c13b41f7d_o.jpg

Whole Image:

http://static.flickr.com/33/52800852_918c7e55d5.jpg

I think it's passable.

― Bombed Out and Depleted / Kate (papa november), Monday, 24 October 2005 00:00 (twenty years ago)

The litmus test will be the print I spose :/ I hate printing! Damn calibration and conversion to CMYK and all that faddle.

― Trayce (trayce), Monday, 24 October 2005 03:37 (twenty years ago)

Awesome photo Kate and I think it will print nicely. If I'm not mistaken, a 3200 x 2400 pixel image would be 120 dpi at about 26 X 20 inches which actually should be plenty of resolution on its own.

― walter kranz (walterkranz), Monday, 24 October 2005 03:52 (twenty years ago)

Cool Walter, thanks for the heads up.

Only problem is Trayce, it's costing me $40 for each print so I'd prefer to get it right the first time :)

― Bombed Out and Depleted / Kate (papa november), Monday, 24 October 2005 03:57 (twenty years ago)

Ouch! Can you possibly do a rough proof first, on a cheaper injet or something?

― Trayce (trayce), Monday, 24 October 2005 04:15 (twenty years ago)

when you change the ppi from 180 to 300 in photoshop (if it's being printed on an epson printer, make it 360ppi), make sure you resample the image as "bicubic smoother" as opposed to "bicubic" or "bicupid sharper." you'll have less loss of quality.

― amanda eileen (amanda eileen), Monday, 24 October 2005 04:18 (twenty years ago)

Cool, thankyou Amanda.

― Bombed Out and Depleted / Kate (papa november), Monday, 24 October 2005 04:19 (twenty years ago)

I've done some rough proofs Trayce, but the paper the final one will be on will be Photo Rag and it makes it hard to tell when my test prints have all been on average inkjet copy paper.

― Bombed Out and Depleted / Kate (papa november), Monday, 24 October 2005 04:21 (twenty years ago)

Genuine Fractals is the program you're looking for. It uses some kind of algorithm to upsample an image, allowing it to be printed much larger than the original file could be. Should be available over the usual filesharing/warez sources, as I doubt you want to spend that kind of money for one image.

It's going to be rough getting a passable image of that size from such a small original file. At the original resolution, printing at 240dpi (low but passable for a large image) you're hitting 13.3x10 inches. I'm not sure just how much extra size GF can give you.

― Are You Nomar? (miloaukerman), Monday, 24 October 2005 04:24 (twenty years ago)

3MB is small!

Geez.

― Bombed Out and Depleted / Kate (papa november), Monday, 24 October 2005 06:55 (twenty years ago)

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