Specifying Pixel Size

[JPotatoes]

This is obviously a newbie question.

We have PSE 5 and ImageReady 7.0 – both Adobe products.

IR is focused on web publishing – dimensions can be specified in pixels, other features tend to focus on web publishing preparation.

I would like to use PSE 5 for photo related work and then publish some of those photos to the web. I cannot find features in PSE 5 that relate to dimensions specified in pixels; everything seems focused on other dimensional units.

Have I failed to find the right feature or will I have to revert to IR for the pixel based image sizing that I occasionally need?

[scrapperjlc]

If you use the Save for Web function in the File menu you can specify how many pixes you want. Is that what you are looking for?

Jodi

[kevq]

If you open a photo in elements you can go to - Image - Resize - Image Size, you can resize the photo by setting the number of of pixels. Hopefully someone who is better qualified will be along to explain the ins and outs.
Kev.

[Codebreaker]

Elements will let you work in units of Pixels if you wish. When you create a New Document you can specify the size in Pixels. Rulers can be set in Pixels. Selections, brushes and many other things can be set in Pixels.

When presented with a drop down box just scroll down to see if Pixels is an option. When entering numbers into option boxes suffix the number with px, eg 300px.

Maybe if you can tell us what it is you can't seem to find we could point you in the right direction - maybe :)

Colin

[JPotatoes]

I was imprecise in my question. Let me elaborate.

My question refers to the ability to have a specific crop window size expressed in pixels.

Assume that I have a picture that has been edited and corrected as desired. Now I want to crop it to a specific size for the image box on a web page. In these cases the image box is always expressed in pixels – 100x125 for example.

Once I have the crop window up and move it around to capture the information I want I can eliminate all of the extraneous stuff.

The result can then be saved to a file with the appropriate jpeg quality to meet reasonable bit densities so the page loads reasonably fast.

That is what IR allows – a crop size based on pixels. Does PSE 5 offer the same type of feature?

[GaryK]

Hi

I just tried cropping in pixels .. you can do it but I don't think it works as you described.

Using the crop tool just type px beside the number for the dimension.

It let me drag the crop box all over the place but it just go a centered small box. I was just trying so I may not have been paying attention to what I was doing.:confused:

[Wendy]

Hi ...

Do you really mean crop it or do you simple want to reduce the size of the whole image to 100 X 125 ??

Wendy

[JPotatoes]

In my case I want to crop the image. In actual practice the box is drawn the correct size and then I can use the arrow keys to exactly move it around the picture.

Possibly I am entirely off base here and if so somebody can enlighten me. Most pictures have too much information and something needs to be trimmed. The IR pardigm takes the whole picture and apparently makes assumptions regarding sampling algorithims appropriate for web display devices. It allows you to specify a crop size box and move that box around the image window. When that has been done, the unwanted stuff is trimmed away leaving a portion of the image that will fit into that pixel size box. Then you 'save as optiomized' and set your jpeg quality metrics and it works.

[Chuck S.]

If you want to crop an exact dimension portion of an image (with no resampling):

Pick the rectangular marquee tool from the toolbar.
Set the dimensions for, say, 500 pixels by 500 pixels and click on your picture. A selection exactly 500 pixels by 500 pixels will appear.
Move the selection around with the arrow keys.
When it's where you want it, do an Image>Crop.Chuick

[pyewackett]

This was a very interesting thread. My background is also web work and I think only in terms of pixels and have no intention of having two numbers floating around in my head, an imaginary size and a dpi.

I was very happy that crop has crop to an aspect ratio because that doesn't exist in Photoshop 6. But I also noticed that if I wanted to crop I couldnt' set pixels. Now I see that one can by typing in 100px and 100px, say, but it sets an aspect ratio and resizes to the size you said! I guess that is interesting but it isn't what JPotatoes and I want.

You can do what Chuck said, which is what I had to do in Photoshop 6, use the selection tool. You can choose fixed size there. You can move the selection marquee after you set it if you are in the correct mode (not add to selection or subtract from selection).

I suppose entering the pixels and cropping and resizing all in one is also useful.

[hukari]

I must be really stupid. I have read this thread three times and still don't understand what you guys need. Anyone got time to explain???

[Codebreaker]

Well, I'm still a little unclear about what your expectations of cropping are, so forgive me if what I say now is a little too basic but it may help clear up the issue.


If you have an image which is 1500 x 1000 pixels and want smaller pixel dimensions ( or larger) without loosing any of the image then the only option you have is to re-sample the image using the Image > Resize > Image Size control. Check the Re-sample box and enter the new Pixel dimensions.

If you don't want all of the image i.e you want to crop something out the centre then you can use the crop tool and specify how many pixels you need. So, for example on our 1500 x 1000 pixel image if you want to crop to a size of 300 x 200 pixels just enter this number. However, the crop box you see is going to be smaller than the original image - naturally because you have less pixels - and it may not encompass all of the part of the image you need. In which case you'll have to crop with different settings to get everything in.

Or maybe you need a combination of both. You Crop the image to get what you want in the picture and then re-sample to get the Pixel dimensions you need.

Take care: re-sampling is an artificial process and if too much is applied image quality may suffer.

Colin

[TonyW]

I must be really stupid. I have read this thread three times and still don't understand what you guys need. Anyone got time to explain???

Reka: You're not alone - I do have Image Ready but never looked too far into it - so maybe it has something there that's a combination of crop (where you set the Aspect Ratio and piece of the image you want to keep) and Save for Web which then lets you set the pixel dimensions and jpeg compression. For any web images I do that's all I need.

Tony

[JPotatoes]

Codebreaker had the key – the term is re-sampling. Nerds like me do not know the nomenclature for image related activities.

I believe that my question was imprecise and that PSE 5 can do what I wanted. To help out those who are confused by this thread here is my understanding.

Assume a 10 mega pixel camera and a picture of a sign and a person – lets call it a scene. The scene has 10 mega pixel of data – lots of very fine grained and detailed pixels that allow the scene to be enlarged and/or fiddled with prior to printing to some physical media at probably 600 to 1200 dpi.

Assume a 2 mega pixel camera and the same scene. The scene has less data and it is fairly coarse grained so enlargement and other effects have less to work with. Printing at 600 to 1200 dpi may have some deficiencies.

Scene size for web developers is focused on pixels – that is the actual size of the monitor real estate that will be occupied. If more pixels are provided to the monitor, there will be too much detail and the scene will ‘overflow’ the display device. A monitor used to view info from the web can be thought of as having a 72dpi resolution (most likely 60 dpi depending on the geographic location and some other nerdy engineering factors) This 72 dpi ‘device’ is the technical constraint used to filter the millions of pixels down to the requisite display information.

PSE 5 has a ‘Save for Web’ option under the File menu. If you select it with any reasonable sized image of good quality (more than several megapixels) you will get a dialog box that warns that “The Image size exceeds the size Save for Web was designed for …”. If you ignore that warning and proceed, and you have a robust computer with a couple of gigabytes of RAM, you next get the opportunity to select image type and quality and then select the pixel size you want and the result is a ‘ready for the web’ picture element of significantly smaller size.

Adobe’s ImageReady program apparently understands the constraints for web display and in its ‘save as’ mode re-samples the data so that the saved scene, initially consisting of possibly millions of pixels, is saved as a small file that will display on the low resolution CRT device at the specified pixel size and look ‘good enough’.

The IR and PSE 5 methods of getting the result are essentially identical. Most likely a bicubic re-sampling algorithm is used that has been pre-tuned for the dpi characteristics of a typical monitor used to display web pages.

Tests indicate that the results of a sample photo yielded identical results in IR and PSE 5. Those same results were essentially matched when a re-sampling approach was used with PSE5 and the image size was constrained.

So to do what I wanted, use crop tools to get the exact scene that is desired and then ‘Save for Web’ option.

[pyewackett]

If you don't want all of the image i.e you want to crop something out the centre then you can use the crop tool and specify how many pixels you need.
I don't "need" any particular number of pixels. What I'm trying to do is crop in the true sense of the word. I don't want some of the picture. Yes, the result will have fewer pixels. If later I need more pixels for printing, say, (which I rarely do) then I can create them then. I don't want any generated pixels unless I ask for them.

I want crop just like Photoshop 6 has it except I'd love to be able to crop to an aspect ratio because generally I want to keep the same aspect ratio so all my pictures have the same shape. So in Photoshop I use selection with fixed aspect ratio and then crop the selection. Done.

I thought Elements had a wonderful feature and didn't notice it was gratuitiously generating pixels for me! If I want to generate pixels I'll ask for it. And I might not even use Photoshop to do it.

[Wendy]

Hi ...

Why not just set the crop tool to the desired ratio ... leave the resolution box empty and crop.

That way the ratio is right, you get the part of the image you want and there is no resampling :)

Wendy