General Cropping Help Needed

[globalmark]

Hi

I am Using Photoshop but am sure this applies to most programs ,
I want to know when I crop a Photo (from 12m pixel camera) how do I keep the Image the best quality , and still crop , I always Take photos in Best quality so I can play Later , but with cropping I have manual options and/or preset sizes (8x10 , 7x5, 4x6, etc) but the original Photos are 12.841" x 9.631" and resolution is 314 Pixels/inch.

I know how to Crop to 10x8, etc. and I can put the resolution in , But whats the best size/resolution to keep the best quality as original i can ( I am not so Bothered about file size to big) just as long as I crop and keep it as good quality as original.

Any Help is appriciated I have read Plenty on google but cannot seem to find this specific answer just how to crop - does not mention what is best to keep great quality. and at the moment I am just guessing whats best .

Thanks

 

[akadmon]

Cropping does not change the resolution. Resizing does.

When you crop, the only pixels that are removed are those in the cropped out area. When you resize, the app (in this case PS) has to throw away pixels to fit the entire image in a smaller area.

 

[Phrasikleia]

For printing you want a resolution of around 300ppi. Digital files from a 12MP camera will have a resolution something like 4272 × 2840 pixels before you do any cropping, so at 300 pixels per inch, you end up with a maximum physical print size of about 14.2 x 9.5 inches.

If you crop the photo, you have fewer pixels to work with and therefore have to print at a smaller size, if you want to keep the 300ppi. Or you can print larger with a lesser resolution. Depending on the printer, doing the latter will result in softness or even "jaggies" showing.

Hope that helps.

 

[Designer Dale]

I think you have cropping and resizing mixed up. Cropping is like taking scissors to a 5X7 and cutting it down to 4X6. You lose image. Resizing takes the whole image and either shrinks or expands it. Like a sponge. You can make a large file smaller without loosing detail (much) but you can't take a small file and make it larger without loosing detail.

The first clipping below shows a 12MP file from a Canon xsi shot in .jpg mode.

The second shows the same image with the resolution increased from 72 to 300 (print quality). The physical size is reduced while the pixel dimensions remain the same. It retains image detail and becomes manageable for printing.

The last one shows the process with Resampling checked on. Resampling either tosses pixels out when making a large image smaller or invents pixels when making a small image larger. Avoid resampling because it causes an image to loosing detail.

My lesson for the day. Anyone feel free to correct me if I missed anything.

Dale

 

[globalmark]

Thanks for all The Help guys

I now Know whats what ,
I am not using Images for printing or anything specific , I have just a Few images I want to crop and save for now , can someone Let me know what is the Best process/way to do it, for me to Crop and resave the new image in relation to size (4x6 8x10 etc) resolution, pixels, whatever

Because at the moment I have loads of great photos of some sea eagles carrying fish But a lot of Blue sky I want to get rid of , but keep the image the best i can as maybe in the future I will do other things with it .
and at the moment I might do the wrong way and gives me a Lesser Quality.

Thanks

 

[Designer Dale]

This is an example of what you want to do. I changed this 4X5 300 dpi image to 72 dpi to show the effects of cropping and resizing (which is what you want to do) more clearly.

The first image is 4X5 at 72 dpi. The second is using the crop tool in PhotoShop draw a 4X5 proportional box that will clear away most of the green and center the butterfly in the same size space. The last is the final product. Note how fuzzy the butterfly is now. That is an effect of cropping and then making it bigger. This was done with my copy of PhotoShop, but I'm sure you can do the same process in iPhoto.

Dale