Which technique ensures that the picture is of the best quality and doesn’t "loose" any information?
2. For sure.
1. If you don’t specify any ppi, it keeps only original pixels. If you specify a ppi, it is going to down or up sample, usually UP.
M
Thanks, but if my ultimate objective is to print a 4×6 photo, using that method leaves me with 512 ppi – way to much info. Resampling seems to be the only way to get down to 4×6 AND 300 ppi. So far my prints actually look good, so the resampling doesn’t have a noticeable detrimental effect.
Jason,
I usually resample to get to a size and ppi that I want for printing. But, I would make sure you save the image to be printed as a separate image and don’t resample and save the original.
Dick
Jason,
There have been extensive discussions here about dpi and ppi. I believe one point was, that it does not hurt to have too many (like 512) ppi. It will harm the image though if you don’t have enough. Roughly 250 – 300 ppi seems to be the consensus for a good print. If you use the crop tool with the resolution box left blank, you will get a different resolution (less ppi) if you crop a smaller portion of the image. Sometimes that may be desirable. Try it and look at Image >Resize >Image Size. The resolution may be much more in range.
Juergen
Downsampling to 300ppi, when you indeed know you ARE downsampling and not upsampling, is fine.
Most newbies who use crop tool think they can pull a small section out and keep a suitable ppi for printing, which generally they can’t unless file happens to be quite high rez to begin with…
Mac
unless file happens to be quite high rez to begin with…
Mac,
….which is the case with his images. 🙂
Juergen
The further point being, though, Juergen…
No matter what you start with, if you use the crop tool with a ppi specified, there is no calculator built in to TELL you if you are upsampling.
After all, a small enough crop specified as say, 300ppi, from even a 100MB image will upsample.
Granted, you can get a pretty good "feel" for it using crop tool with ppi specified, but there’s nothing built into the tool to let you know if you are Upsampling or Downsampling.
M
Mac,
Agreed. I was suggesting to leave the ppi unspecified (empty box), crop and see what the result is. If the section is smaller than the original, you’ll have less ppi. Jason was concerned having to much rez. It may be considerably less after cropping and he might not have to worry about downsampling. Just a thought… 🙂
Juergen
Mac,
Let me further this a bit. Most my prints are 5×7. The images of the camera are 2272×1704 at 180 rez, or 12.622 x 9.467 inches. If I crop by selecting with the crop tool the whole image (except for a small strip to accommodate the change from 4×3 proportion), I will have an ‘instant’ 324 rez which is just fine for printing. I just think this is an easy and simple approach always keeping in mind to check the actual rez before printing.
Juergen
I use your #2 procedure and I let the resolution remain high as you indicated. I load them back on to the flash card (after clearing the flash card)and take my 4 x 6 photos to a kiosk. The kiosk has no problem handling the high resolution. They have always turned out great.
HTH
Ben
I’m using the number 2 procedure – crop to a 6 to 4 ratio and then resize down to 300ppi using image size (simply to get more photos on the card – I’m doing a big batch of prints). A local processor using a Fuji Frontier has a Really Good deal – by Australian standards, which means the per print cost is about the same as the normal US prices I see referred to, so I’m going through all my digital camera shots (that’s two and a half years worth!) and sorting out to get around 100 family snapshot album type images to get printed onto archival paper. The Kodak camera images are easy as they are 6×4 at 300 ppi to start with. The ones from my Canon G3 are more of a nuisance as some of the best ones simply won’t crop to that proportion. It’s too narrow. I much prefer a squarer shape. I wish the larger print sizes were affordable, then I could afford to leave blank margins but on 6x4s you end up with rather too small a print area.
It’s interesting going through that many photos with a more critical eye… although in this case I’m as much looking for making sure I’ve got prints of all the members of the family over the time frame as I am photo quality. One scary thing, I found that a whole folder of original images had been accidentally deleted from my hard drive somehow – luckily I have CD backups to restore them.
Oh, I understand exactly, Juergen…
And for folks like you who understand the process, that’s of course a great workflow.
I’m just always mindful of all the folks in here who are starting with these 1 and 2 MP images, cropping them by half and wondering why they don’t get nice 8×10’s 🙂
M
"Most photographers do their printing these days with a desktop inkjet printer and the Epson Photo printers are the most popular so I’ll use them by way of example. These printers, such as the models 870/1270/2000P are (somewhat misleadingly) listed as 1440 dpi printers. This means that they are capable of laying down that many dots per inch. But, to create a colour image they need to use 6 different inks, so any particular pixel reproduced on a print will be composed of some dithered composite of coloured dots using some or all of these inks. That’s why you need more dots from your printer than you have pixels in your image.
"If you divide 1440 by 6 you end up with 240. This is the true minimum resolution needed to get a high quality photo-realistic prints from a 1440 dpi Epson printer. Many user, myself included, believe that a 360 ppi output file can produce a somewhat better print. If my original scan is big enough to allow this I’ll do so but I don’t bother ressing up a file to more than 240 ppi when making large prints."
From:
<
http://www.luminous-landscape.com/tutorials/understanding-se ries/und_resolution.shtml>
On Fri, 16 Jul 2004 20:36:26 -0700, wrote:
"If you divide 1440 by 6 you end up with 240. This is the true minimum resolution needed to get a high quality photo-realistic prints from a 1440 dpi Epson printer.
Stu,
Isn’t it a little more complicated than that, because of the different algorithms used by various printers to relate ink droplets to pixels?
http://rpdfaq.50megs.com/#Section_5-5 But maybe the printer manufacturers should make it clear that their "dpi" means "droplets per inch" and not "dots per inch".
OldnSenile
