Resampling via Crop Tool

[sleepeng]

Hi everyone,

I am currently making a MyPublisher photo book of my Costa Rica trip, and am nearly finished. I have a question about resampling in Elements. Since MyPublisher recommends that the images used for the book be 180-200 dpi, I've been downsampling the images taken with my Canon Rebel XT with the crop tool by changing the dimensions and resolution. However, after cropping each image, I have been going to the Image Size dialog box and checking "bicubic sharper" because I read somewhere that "bicubic sharper" is the best interpolation format when downsampling. (Is this even true? I think I've seen different opinions.)

By doing this extra step, have I accidentally been interpolating the images twice all along and futher degrading the images? In other words, does resampling with the crop tool automatically interpolate with the default "bicubic" format even without me opening the Image Size dialog box? (I was not able to figure out how to get the default changed to "bicubic sharper" - the option doesn't seem to be in "preferences.") I just realized this possible mistake towards the end of my editing process. I would hate to have to redo all the images, so if I messed up, hopefully it won't make that much of a difference (11x8.75 will be the largest image size in the book).

Thanks in advance! :) (I stumbled upon this forum in trying to research this topic, and this is my first post. Can't wait to learn from other members!)

Sandra

[GaryK]

Hi Sandra

Welcome to the forums:)

Sorry I can't be of much help.
I do recall a discussion about how the crop or for that matter just the move tool resamples when resizing but I can't recall what was decided upon. Or even if there was a definative answer.
I am not aware of any way to change the default in those modes although there very well might be.

I know, not much help. :rolleyes:

[OFD678]

When you cropped each photo, did you set the DPI or did you leave it open in the crop options? If you set it manually, what DPI did you set it for?

What other changes did you make in the Image size box?

From what I understand, bicubic sharpening for downsampling is the right choice.

I don't know how the program resamples when you crop and change the DPI either by input or by default. That is a great question.

[sleepeng]

Brent,

When cropping each photo, I did the following:

I set the DPI at 180 or 200 and the estimated document size for each photo, then crop. I then go to the image size box only to select "bicubic sharpener," (the image size box already shows the pixel dimensions and document size that I set when cropping so I don't need to mess with those). When I first open the box, the "resample image" box is by default checked at "bicubic." What I am not sure about is, does this mean that at the time I crop the image, it is automatically resampled with bicubic? If so, is it harmless to change the interpolation method to "bicubic sharpener" if I'm not changing the pixel dimensions or document size again? Or should I just crop and move on, without going into the "image size" box (or figure out a way to make "bicubic sharpener" the default method)?

I hope this all makes sense. Thanks!

[OFD678]

Hi Sandra,

It makes perfect sense, but I don't know what the default mode for croping is. Sorry.

Someone will and they will be able to tell us shortly.

I would take a guess that you only need to crop and not change the image size as this is doing just about the same thing. I would also guess at 200 DPI, it is not going to make a big as difference as it would if you were doing 300DPI.

I am suprised that the printing is done as low as 175 DPI, but I han't done a book yet. Most prints are recomnded at or near 300 DPI, but it really could be different for print in a book. I know the posters I do are 200 DPI, but the reason is you stand further away from a poster and it is much larger.

Sorry I could not answer the specific question...but some one will.

Thanks
Brent

[Juergen D]

Sandra,

Doing some experimenting here, I would assume that resampling with the Crop tool uses Bicubic, because it is the default when going through >Resize. I could be wrong, but changing the setting to Bicubic Sharper in the Resize dialog does not stick when doing another action and going back there later.

If you have cropped and set your resolution to 200 ppi (it's ppi not dpi, MyPublisher has that wrong ;) ) using the Crop tool, then go back to the >Resize dialog box and change the setting to Bicubic Sharper and click OK, nothing happens. You can apply the different setting by changing something else in the box, e.g. up the resolution to 210 ppi. In my test, I could not see any difference in the image, though.

Juergen