Picasa/PS CS2

[Sonny]

I use Picasa 2 to view and quickly crop SOME photos. Tonight I cropped a photo using Picasa 2 to 8x10. Imported into PS CS2 for some editing. I noticed under IMAGE SIZE the info read as followed:


Pixel Dimensions: 10.5M
Width: 1716p
Height: 2147p

Document Size:
Width: 23.833"
Height: 29.819"
Resolution: 72 p/inch

Then I took the original photo and used PS CS2 to crop the photo to an 8x10. Here's the info:

Pixel Dimensions: 20.6M
Width: 2400p
Height: 3000p

Document Size:
Width: 8"
Height: 10"
Resolution: 300 p/inch

Why such a difference between the two photo cropping them to and 8x10?

[srwatters]

They are the same ratio, but you actually did an upsize interpolation when cropping it to an 8x10. To start with don't look at the Document size portion of the information. The ratio should be 4x5 and it is. Then look at the resolution. For display on a computer, 72 dpi is the default resolution, so Picasa 'assumed' your target meduim is the screen. When you used the crop tool in PS, you had the resolution set to 300 dpi, so Photoshop dutifully interpolated the missing pixels and gave you 2400x3000 or 4x5 ratio at 8x10 inches at 300 dpi. If you truly want to crop, leave the resolution field blank for the crop tool and you will just 'chop' the image down to the pixels you select. If you want to crop and interpolate up or down, then fill in the desired resolution.

[ndsimm]

Originally Posted by srwatters

They are the same ratio, but you actually did an upsize interpolation when cropping it to an 8x10. ....

OK, so we are gonna need a post on digital image definitions

[Sonny]

Originally Posted by srwatters

They are the same ratio, but you actually did an upsize interpolation when cropping it to an 8x10. To start with don't look at the Document size portion of the information. The ratio should be 4x5 and it is. Then look at the resolution. For display on a computer, 72 dpi is the default resolution, so Picasa 'assumed' your target meduim is the screen. When you used the crop tool in PS, you had the resolution set to 300 dpi, so Photoshop dutifully interpolated the missing pixels and gave you 2400x3000 or 4x5 ratio at 8x10 inches at 300 dpi. If you truly want to crop, leave the resolution field blank for the crop tool and you will just 'chop' the image down to the pixels you select. If you want to crop and interpolate up or down, then fill in the desired resolution.

Which way will give me better looking quality? Thanks for the help!

[srwatters]

Originally Posted by ndsimm

OK, so we are gonna need a post on digital image definitions

Upsize
Interpolation

[ndsimm]

upsize i kinda already had.....interpolation...well that's another story...thanks

[shutterflypro]

You are trying to get a bigger image out of a smaller one. You need to becareful here. Photoshop will be the one that will handle this the best. Its graphics engine is just better adept at it.

Your best bet is to leave the image in its native dpi (basically whatever it is right our of the camera ie. mine is 240) Then you should resize your image in 10% increments until you reach your wanted size. After doing that you can then Crop to your desired ratio.

By increasing your image size in 10% increments you will limit the amount of artifacts and fuzzyness appearing in your photo.
Hope I didn't confuse you too much.

Originally Posted by korrupt

Which way will give me better looking quality? Thanks for the help!

[CaptainTom]

In Picassa2 when you export, make sure your image size options button is selected to
"original size"........

[srwatters]

Originally Posted by shutterflypro

You are trying to get a bigger image out of a smaller one. You need to becareful here. Photoshop will be the one that will handle this the best. Its graphics engine is just better adept at it.

Your best bet is to leave the image in its native dpi (basically whatever it is right our of the camera ie. mine is 240) Then you should resize your image in 10% increments until you reach your wanted size. After doing that you can then Crop to your desired ratio.

By increasing your image size in 10% increments you will limit the amount of artifacts and fuzzyness appearing in your photo.
Hope I didn't confuse you too much.

Prior to Photoshop CS2, I would agree with you, but PSCS2 has a new option called bicubic smoother. There is an excellent article in this months Digital Photo Pro with quantitative proof that a single upsize using the new option is just as effective and indistinguishable from the old 10% method. There is also a good writeup on ACR3.1 and using the adjustment tabs and curves to get the most out of your RAW images. I highly recommend this magazine.

And to answer the original question, use Photoshop. It's the right tool for the job.

[Sonny]

Originally Posted by shutterflypro

You are trying to get a bigger image out of a smaller one. You need to becareful here. Photoshop will be the one that will handle this the best. Its graphics engine is just better adept at it.

Your best bet is to leave the image in its native dpi (basically whatever it is right our of the camera ie. mine is 240) Then you should resize your image in 10% increments until you reach your wanted size. After doing that you can then Crop to your desired ratio.

By increasing your image size in 10% increments you will limit the amount of artifacts and fuzzyness appearing in your photo.
Hope I didn't confuse you too much.

These images are jpegs from my 20d.

Pixel Dimensions: 23.4M
Width: 3504p
Height: 2336p

Document Size:
Width: 48.667"
Height: 32.444"
Resolution: 72 p/inch

[srwatters]

Originally Posted by korrupt

These images are jpegs from my 20d.

Pixel Dimensions: 23.4M
Width: 3504p
Height: 2336p

Document Size:
Width: 48.667"
Height: 32.444"
Resolution: 72 p/inch

I was sort of confused about all this pixel and resolution stuff when I got started in digital. Here is my method when resizing and cropping.

You have an 8MP 2x3 ratio image out of the camera.
If you want to make an 8x12 print your native resolution would be 292 pixels per inch which is more than enough for a 8x12. If all you do is chop from the long side without reducing the short side of the image, you still have the native 292 ppi. It's when you chop down the short side that you will either lower the resolution or need to interpolate to resore the missing pixels. Personally I think anthing greater than 240 ppi makes great 8x10 or even up to 11x14. Once you get bigger than that, you can actually lower the resolution since the viewing distance will be greater and larger pixels won't matter as much.

I hope this makes sense. It took me a little while to get my noodle to keep it all straight.

[CaptainTom]

I hope this makes sense. It took me a little while to get my noodle to keep it all straight

So Scott, do you prefer chopsticks or regular fork for your noodles ?????