losing resolutions in photos when editing

Brenhaven

Welcome to the Apple user discussion forum

However when I perform an edit such as crop to 8x10 it reduces the resolution when it crops it. it reduces the resolution so much that you can no longer print the photo as an 8x10

A couple of questions - how are you editing (and cropping) - using the iPhoto editor or an external editor - if so which one and how do you access the iPhoto library

Before you edit look in the info window at the lower left and see that the pixel dimensions of the photo are and then note them again after you edit - what are the dimensions before and after?

LN

brenhaven

The photos downloaded from my camera to my Mac are pretty large 4-15MB.

These are RAW file, yes? Are you editing the RAWs or the jpeg previews?

Regards

TD

15 MB is a pretty huge jpeg.

Whenever you edit a jpeg there is added compression. iPhoto's compression is about the same a 8 on Photoshops scale of 12, according to Old Toad who has tested this. There is no way to change the compression rate.

If you're not content with this then use Elements for editing.

You can set Photoshop (or any image editor) as an external editor in iPhoto. (Preferences -> General -> Edit Photo: Choose from the Drop Down Menu.) This way, when you double click a pic to edit in iPhoto it will open automatically in Photoshop or your Image Editor, and when you save it it's sent back to iPhoto automatically. This is the only way that edits made in another application will be displayed in iPhoto.

Regards

TD

Hi brenhaven: I just experimented with the same idea as you stated of cropping to an 8X10. Starting from an original size of 3888x2592 pixels at approx 4.9mB. When cropped to 8X10 it results in a file that is 3240X2592 pixels at approx 3.4mB.

I'm using iPhoto '08.

Stedman

Are you seeing any obvious image degradation? Even though there is jpeg compression taking place when editing in iPhoto I've not been able to detect any obvious image degradation when printing pictures. Although I've not printed any larger than 8x10.

If you are seeing image degradation that is objectionable then you can set up Photoshop Elements as your editor of choice in iPhoto.

Using Photoshop (or Photoshop Elements) as Your Editor of Choice in iPhoto.

1 - select Photoshop as your editor of choice in iPhoto's General Preference Section's under the "Edit photo:" menu.

2 - double click on the thumbnail in iPhoto to open it in Photoshop. When you're finished editing click on the Save button. If you immediately get the JPEG Options window make your selection (Baseline standard seems to be the most compatible jpeg format) and click on the OK button. Your done.

3 - however, if you get the navigation window that indicates that PS wants to save it as a PS formatted file. You'll need to either select JPEG from the menu and save (top image) or click on the desktop in the Navigation window (bottom image) and save it to the desktop for importing as a new photo.

This method will let iPhoto know that the photo has been editied and will update the thumbnail file to reflect the edit..

NOTE: With Photoshop Elements 6 the Saving File preferences should be configured: "On First Save: Save Over Current File". Also I suggest the Maximize PSD File Compatabilty be set to Always.

If you want to use both iPhoto's editing mode and PS without having to go back and forth to the Preference pane, once you've selected PS as your editor of choice, reset the Preferences back to "Open in main window". That will let you either edit in iPhoto (double click on the thumbnail) or in PS (Control-click on the thumbnail and seledt "Edit in external editor" in the Contextual menu). This way you get the best of both worlds

2 - double click on the thumbnail in iPhoto to open it in Photoshop. When you're finished editing click on the Save button. If you immediately get the JPEG Options window make your selection (Baseline standard seems to be the most compatible jpeg format) and click on the OK button. Your done.

3 - however, if you get the navigation window that indicates that PS wants to save it as a PS formatted file. You'll need to either select JPEG from the menu and save (top image) or click on the desktop in the Navigation window (bottom image) and save it to the desktop for importing as a new photo.

This method will let iPhoto know that the photo has been editied and will update the thumbnail file to reflect the edit..

TIP: For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto (iPhoto.Library for iPhoto 5 and earlier) database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've created an Automator workflow application (requires Tiger or later), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 6 and 7 libraries and Tiger and Leopard. iPhoto does not have to be closed to run the application, just idle. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.

stedman, I share brenhaven's pain! With iPhoto '08, if I do as you do and take a photo with an original size of say, 3888x2592 pixels at approx 4.9mB, as you did and crop it to an 8X10, it goes from being a 300 dpi picture suitable for printing to and 8X10 at 72 dpi. What I want is an 8X10 at 300 dpi. It sounds like you were able to achieve within iPhoto what brenhaven and I could not Please explain! The goal here is to maintain the same resolution and simply to crop the picture.

glindsey

What are the pixel dimensions of the pic when you crop it. iPhoto routinely displays edited versions at 72dpi but compensates by changing the length and breadth.

Regards

TD

Regarding the dpi readThe Myth of DPI.

Hi Terrance and Old Toad,

Aha! I think I kinda, sorta "get it" in terms of what iPhoto is doing. But how it handles resolution is still a bit confusing. The article on "The Myth of DPI" that Old Toad recommended helped a lot. Thank you!

Now, for the confusing part. Yes, the iPhoto program does display the pictures at 72 dpi but makes up for them in terms of breadth and width, as you explained Terrance. So, my original photo which was 988 KB and was 971X1423 with a width of 3.237inches and height of 4.743inches with a 300 dpi (Photoshop measurements) cropped in iPhoto to a 3X4, displays in iPhoto when clicking on "get information" as being only 503 KB with dimensions of 971 X 1295 pixels. Then if you export this cropped iPhoto picture at maximum quality into Photoshop, you see that it now has a width of 13.486 inches and height of 17.986 with a resolution of 72 dpi.

But what I would expect to see is that the photo when cropped to a 3 X 4 picture, that it would still maintain its 300 dpi and simply reduce the pixel dimensions to 900 X 1200 pixels per inch.

I realize, of course, that the pixels are still there, and that the dpi doesn't really matter in the long term because the picture quality is still the same whether it's a 3 inch X4 inch print at 300 dpi or a 13.4 inch X 18 inch print at 72 dpi, but the difference in how Photoshop and iPhoto handle cropping does take some getting used to.

Also, I think once I get used to iPhoto, I might even prefer its methodology for handling print resolutions better than Photoshop because it allows you to keep a single picture on file and then, based on whether you want to email it or print it, specify its intended size. But like I say, it does take some getting used to!

On another note, I tried exporting this same photo in the 4 different quality files available in iPhoto for export with interesting results. All of the files produced photos with the dimensions of 13.486 inches X 17.986 inches with a resolution of 72 dpi, with the only difference being the size of the file. In other words, the low quality photo was 92 KB; the medium quality file was 188 KB; the high quality file was 340 KB; and the maximum quality file was 504 KB. But when each of these files was opened in Photoshop and viewed under image size, they appeared identical. What gives?

As to iPhoto's default displaying at 72 dpi, well it has to display at something and most monitors are 72 dpi. But perhaps you can change their mind...

iPhoto menu -> Provide iPhoto Feedback

But when each of these files was opened in Photoshop and viewed under image size, they appeared identical. What gives?

The extent of jpeg compression is what's at play here. More and more information has been thrown away, so the file size is smaller. The miracle of the jpeg compression algorithm is such that it is difficult to see the difference on screen - you might notice it more on printing. 😉

Regards

TD