How to do an "accurate" crop mask in iPhoto

[DerChef]

Maybe I am being really thick or somnething. I go into edit mode ater selecting the picture I want . Hit the constrain button to say my desktop resolution of 1024 X 768 and a greyed out crop mask comes up on the screen that you can move about.

However it Aint 1024 x 768 or anywhere close its much bigger

Same thing happens If I custom select the resolution well at least I assume its pixels it has two unlabelled boxes.

What gives might try reinstalling gimp again or how to do you do a crop mask in graphics converter

 

[mkrishnan]

I think you're confusing cropping and re-sizing. When you constrain to the desktop, you don't constrain to the actual pixel size of the desktop -- you constrain to the *aspect ratio* of the desktop. Camera images don't typically have the same aspect ratio as the screen, so if you do this, you get clipping on two sides.

When you crop, you eliminate part of a picture, without scaling it. If you were to take a 5 or 6 megapixel picture and *crop* it to the desktop's pixel dimensions, you would only get a very small part of the image, because it has so many more pixels than your desktop res.

It sounds like what you want is to crop an image to desktop aspect ratio and then re-size the remaining portion of the image to the desktop resolution. If you do that, you will get an image that contains most of the features in your original photo, but at a lower resolution.

Is that right?

Or do you want an actual 1024x768 crop mask over a much larger image? If so, why?

 

[DerChef]

Or do you want an actual 1024x768 crop mask over a much larger image? If so, why?

Basically Pictures of Motorsport native size 3072 X 2048 photos want to crop them to showing car only without adverts , spectators and the like.

I can do this easily on a PC with Paint shop Pro in just a few mouse clicks. Naturally on some of them I will have to resize the picture first as it is far too big if what I want already fills the frame. However most of them I would rather do a crop mask over the full resolution of the picture if I can.

PS I have just found a Mac program that CAN do with I want and its Canon Image Browser but if limited in other areas.

 

[DerChef]

I think you're confusing cropping and re-sizing. When you constrain to the desktop, you don't constrain to the actual pixel size of the desktop -- you constrain to the *aspect ratio* of the desktop. Camera images don't typically have the same aspect ratio as the screen, so if you do this, you get clipping on two sides.

?

PS why is the Custom option inaccurate than in the crop area it produces then

 

[neocell]

I might be missing something, but why don't you just select the portion of the picture that you want to keep and then select crop from the Image menu then save as?

 

[DerChef]

I might be missing something, but why don't you just select the portion of the picture that you want to keep and then select crop from the Image menu then save as?

Yes I know you can simplly drag over a selection BUT as the other poster said I want it to be in the screens aspect ratio and not simply a random shape and preferably with a mask brought up that I can move around on the screen that is the exact size I want.

It all seemed so easy on the PC with Paint shop Pro, Photoshop and almost every other image editing software

 

[mkrishnan]

It all seemed so easy on the PC with Paint shop Pro, Photoshop and almost every other image editing software

Ya know, they make PS for Macs too.

Hummm, okay, so you want a cropped image, but you want the crop to have the right aspect ratio, right? That makes sense. If you want prints, or you want to use them as desktops, etc, you need specific aspect ratios.

If you choose a constraint for the crop mask in iPhoto, you get a box, right? But that box is much bigger than, say 1024x768, because it still contains most of the picture. The box nonetheless has the same aspect ratio as the screen. If you drag a corner of the box to make it larger or smaller, it will remain constrained.

There is no tool in iPhoto like in PS where you can pick the exact dimensions of the cropped box and then move it around the image, but that's because in iPhoto's world, the actual resolution of the image is never really relevant -- you want to keep the image in as high a resolution as possible.

Anyway, yeah, I understand what you want now. If you don't care about the pixel dimensions (but only the aspect ratio) of the final image, in iPhoto, you can choose a constraint and then resize the mask. Otherwise, you have to go to PS or GIMP, etc.

 

[DerChef]

Well I was thinking this way myself . I cant justify the cost of Photoshop. Dont know what "Elements" is like for Mac but the PC version I found a very poor value for money product with a lack of many features found in other software at a similar price (e.g. channel mixer). I would deffo not buy and hope with it.

Might trying installing GIMP again but its interface did my head in PLUS Tiger seemed to break it but I now think that it a repair permissions might have sorted it.

 

[neocell]

Sorry about the previous post, obviously I missed your point. Have you gone to show info just to make sure your photos are acutally ~3k by 2k. Seems strange that iPhoto wouldn't use the correct sized crop box if you selected contrain to 1024x768. Just tested it out on mine and it seems to work appropriately