Hi Laura, Re ICC profiles, Wikipedia says:
> In color management, an ICC profile is a set of data that characterizes a > color input or output device, or a color space, according to standards > promulgated by the International Color Consortium (ICC). Profiles describe the > color attributes of a particular device or viewing requirement by defining a > mapping between the device source or target color space and a profile > connection space (PCS). More here: <http://en.wikipedia.org/wiki/Icc_profile> Basically all your inputs, outputs and monitors have different colour characteristics and the profiles are used to try and maintain consistent results when working with images (you had similar considerations with film cameras and different film types and photo paper types). Say you start with an object - it has a certain colour. Now you photograph it. With a digital camera you get a file of electronic info, since different cameras have different lenses, sensors and adjustment algorithms the actual files produced will vary from camera to camera. Similarly with scanning, different scanners have different characteristics. Then you want to edit the image on your computer - you are doing this by looking at a representation of the image on your monitor and different monitors have very different characteristics. Then you need to print it and again different printers/different characteristics. The profiles are used to try and compensate for the different characteristics of all these devices - so that when you are looking at your monitor you hopefully see a good representation of the original object which you can then print as a good representative image. The above is an over simplification of a very complex area (and I am certainly no expert!) - there are many books, references and courses covering the area in varying levels of detail (depending how masochistic you are). This page <http://www.color.org/profile_embedding.xalter> tells you a bit about embedding the ICC profiles in image file formats. In your case however it seems embedding the profile was causing iPhoto problems but luckily Ronni was able to see through all the techno-murk and solve your problem :) Cheers Neil -- Neil R. Houghton Albany, Western Australia Tel: +61 8 9841 6063 Email: n...@possumology.com on 3/6/09 5:09 PM, Laura Webb at el...@iinet.net.au wrote: > Hi Neil > > Thank you for taking the time to explain all about scanning as .tiff > rather than .jpg. I learned a lot from what you wrote and have kept > your email for future reference. > > As it turned out Ronni was able, as she so often is, to pin point the > problem. Familiar with the Epson scanner I am using, her suggestion > to uncheck the option "Embed ICC Profile" immediately solved my > dilemma. I can now scan B&W photos as .jpg directly into iPhoto. > Perhaps, given your information, not as high quality as they might > otherwise be, but for the time being they are adequate for my needs. > > I might add I have no idea what "embed ICC Profile" means!!! > > Thanks again > > Kind regards > Laura > > > On 29/05/2009, at 2:50 PM, Neil Houghton wrote: > > 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 -- 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:wamug-unsubscr...@wamug.org.au>
