Resolution and peripherals

Tel, a week or so ago, there was an extremely lively (!) discussion on the issue of resolution. I’ll post a link to that (which includes links to two prior threads on the subject – a couple of which went off track.)

All of this still isn’t as straightforward as we’d like it to be. I can give you my views on each of your questions, and that ought to be good to start another spirited debate, too! 🙂

1. "Doesn’t this mean we can forget about resolution of a picture when sending it to a printer?"

I still think not, because that leaves too much room for misinterpretation. If the image has adequate or better resolution to begin with, the answer would most likely be ‘yes.’ However, if we were to make a blanket statement like this, then we’d probably have people sending images to their printer at 72ppi and then screaming because the quality was so poor. At the other extreme, people could be sending images to their printer at 800ppi and then complaining because their printer was too slow. I still think there’s a place for human intervention myself.

2. "Shouldn’t we save images in their original resolution even if they’re going to a device with a lower resolution?"

I am a firm believer in archiving all images in their original resolution. But how are you defining the "device with a lower resolution"? Printers do have resolution, but the resolution of an image file isn’t measured in the same way as the resolution of a printer or of a monitor. Traditionally (although "tradition" in this sense hasn’t been over a very long period), image files were measured in terms of pixels per inch (ppi) and printer resolution was measured in terms of dots per inch (dpi). Monitors are dpi, too, but dpi on a monitor can’t be assumed to be the same as dpi for a printer. This question isn’t as simple as it sounds! 🙂

3. "If we scale an image down, shouldn’t we allow the resolution to go up, ie not dump any information by resampling."

In general yes, but there could be a limit. Some of the larger cameras nowadays simply contain so much digital information, that reducing the size to, for example, a 4 X 6 print without resampling might create a monster file when one really isn’t needed. This is a case in which working from a copy and doing some downward resampling might be in order, but it’s better to work with specifics than generalities.

As to your statement about tomorrow – most definitely, which is why I’m such a strong advocate of archiving all original images and maintaining every last pixel.

Here’s that link, and just skip over the couple of posts that are, um, not too productive…

Richard Lynch "Printer Resolution, one more time" 10/4/03 8:38am </cgi-bin/webx?13/29>

Hi Tel,

OpenGL is alive and well, but I’m not certain it was ever intended for use in images such as photographs.

There are a large number of screen savers, things like Apple’s iTunes Visualizer, games and other applications that use, or can use, OpenGL for 2D/3D rendering. Most of what I’ve seen that uses OpenGL involves motion as well.

Have a look at <http://www.opengl.org/> for up to date details.

HTH

Kyle

Hi Beth et al,
Thanks for your replies, I didn’t have the energy to wade through all of the printer thread, it was that thread that prompted my question, believing that an excessive resolution shouldn’t matter if the printer interface was doing it’s job.
As long as there are not a specific demands from a commercial printer (I shall be needing their services shortly) and if the only reason is to keep down the printer’s processing time and we can rely on the interfaces to interpolate images correctly then I can quite happily send the 800 ppi of a shrunken image off to my printer at home and go and get a coffee, I don’t do that many prints.
Oops, sorry about the involved logical conditions there…

I agree there will be limits but who knows, if you one day want to print an A2 image of that coffee bean and you have the resolution to do it …. so I’d agree there will be an upper practical limit but keep the original. The lower limit I was rather taking for granted.

Tel.