Hi Laura, Not sure if this will help but here goes.
You probably know that jpg files are compressed (to varying degrees depending on the quality chosen) the trouble with editing these files is that every time you change and save them they get re-compressed and each time you lose a bit of quality - a bit like copying the old VHS video tapes (always copy the original don't copy the copies). Because of this, the general rule of thumb is to do any editing work in an uncompressed (or at least lossless) format and only when you have finished make a compressed jpg file. In your case, I would scan the files as TIFF files (which is supported by iphoto) then do any cropping or other editing. When you are happy with your final photo, save as a jpg (I usually save a copy of the edited TIFF file as well - just in case I want to do any further changes). The point is that you don't have to (and shouldn't if you intend to edit) scan as jpg to end up with jpg. You say you can open your .pct files and work with them OK - you could then save them as jpg files from iphoto ready to upload to snapfish (you need to use the export function in iphoto and chose jpg from the options). The main reason I would use TIFF (.tiff or .tif) rather than .pct is that TIFF is a pretty universal file format whereas .pct is mainly a mac file format - but it should all work with .pct the same. With the resolution, given plenty of hard drive space, I would always start with a higher resolution scan than you need for the final print. You have to remember that the image file is just pixels - you scan the image at x pixels/inch and then print the image at a setting of y dpi (dots per inch) if x & y are the same then a scanned image will be printed at the same size but you can and may well want to change the resolution between scanning and printing. Wikipedia probably explains it better than me: > DPI refers to the physical dot density of an image when it is reproduced as a > real physical entity, for example printed onto paper, or displayed on a > monitor. A digitally stored image has no inherent physical dimensions, > measured in inches or centimetres. Some digital file formats record a DPI > value, or more commonly a PPI (pixels per inch) value, which is to be used > when printing the image. This number lets the printer know the intended size > of the image, or in the case of scanned images, the size of the original > scanned object. For example, a bitmap image may measure 1000×1000 pixels, a > resolution of one megapixel. If it is labeled as 250 PPI, that is an > instruction to the printer to print it at a size of 4×4 inches. Changing the > PPI to 100 in an image editing program would tell the printer to print it at a > size of 10×10 inches. However, changing the PPI value would not change the > size of the image in pixels which would still be 1000×1000. An image may also > be resampled to change the number of pixels and therefore the size or > resolution of the image, but this is quite different from simply setting a new > PPI for the file. Quite often you might want to start with a number of photos of the same size and end up with a number of printed images the same (or similar) size but have some photos where you want to crop the image to get rid of unwanted stuff around the edges. If you leave the resolution unchanged then obviously cropping the photo would result in a smaller printed image but by changing the resolution scan you can crop the image and then re-size the cropped image back up to the desired print size. This would result in a lower resolution - so by starting with a scan of a higher resolution you can still maintain a high print resolution. Forgive me if the above seems to be stating the obvious - I guess my point is that you can always reduce a higher resolution without losing any quality other than that implied by the reduced resolution whereas trying to increase image resolution using software is never as good because the software has to "invent" the missing information by extrapolating the existing info. Hope that helps. Cheers Neil -- Neil R. Houghton Albany, Western Australia Tel: +61 8 9841 6063 Email: [email protected] on 29/5/09 1:10 PM, Laura Webb at [email protected] wrote: > Please can someone help me with my problem. > > So far I have scanned 12 of a number of old B&W photos to use in a > Birthday Book project. > > As recommended recently by Susan, I am using Snapfish to upload my > photos before creating the book. It seems ideal for my purpose but > some of the editing tools e.g. cropping, are not available to Mac > users. So I need to put the B&W photos into iPhoto to edit them > before uploading. > > The scanned images are in a folder on the desktop from where they can > be viewed without any trouble at all. However once in iPhoto they are > black, no image at all. I've tried using some of the adjustments > available to no avail. > > Then I discovered that if saved as .pct rather than .jpg I can put > them into iPhoto edit them and do whatever I wish with them. The > trouble with that idea is that to upload to Snapfish photos have to > be jpg. So I scanned them all again as jpg but, apart from three > photos which, for some unaccountable reason are perfect, the rest are > blanks when put in iPhoto. > > Would the resolution at which the photos are scanned have something > to do with the problem? This is currently 300 dpi and why it works > with some but not all photos is quite beyond me. > > Kind regards > Laura > > > > > -- The WA Macintosh User Group Mailing List -- > Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> > Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> > Unsubscribe - <mailto:[email protected]> -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
