Placing images in Illustrator CS5

Question

When I place images in Illustrator CS5, I face the following problems.

• I have a AI-CS5.1 file which is 902 KB in size.
• I have a image file in JPG format which is 618 KB in size. The File is 1600 X 1200 and at 180 dpi. Adobe Photoshop "Image Size" shows it at 5.49M "Pixel Dimensions".
• When I place the file in Illustrator and resize to 460 X 330, the size of my AI-CS5.1 file increases to 11,366 KB. I have to do this for many images and many AI files as I place around 5 to 8 images in my AI files. This causes the size of my AI files to increase from 150,000 KB to 250,000 KB. This in return cause my files to take from 1 to 2 minutes to open. Also when the AI files are saved as PDF, the Acrobat files also have huge file sizes from 120,000 KB to 200,000 KB.
• I tried to open the image file in Adobe Photoshop CS5 and resize/resample to my required size of 460 X 330. Than I place the image file (Which now has a size of 193 KB and 460 X 330). However when I do this, the size of the image in ILLustrator turns out to be 184px X 132px.

All my Raster Settings are at 300 as this is for print. I have no idea why my image file when opened in Adobe Photoshop CS5 has different size from where when I import it in Adobe Illustrator CS5.1. I tried to do this for other files as well thinking that some thing must be wrong with the image file. But the problem remains the same with other image files as well.

I am guessing (the best I can do since I am not a designer) that this problem has to do with the resolution. Nor I am a user of Photoshop. I read Image Resolution, Pixel Dimensions and Document Size in Photoshop to better understand the problem. However I fail to understand the reasons for my problem.

Help would as always be appreciated.

Answer 1

• JPG is a compressed format. When you place images in Illustrator they are uncompressed. File sizes increase.

• You may not want to use jpg for print production. It would be much better to use a simply .psd file to ensure quality is correct.

• If you re-open a jpg image in something like Photoshop and then re-save that image as a jpg you damage the image quality. This happened each and every time you open a jpg, then save it as a jpg. The quality continually will get worse. You should never open a jpg, then save it as a jpg.

• Illustrator, being a vector application, is resolution independent. The resolution, document raster effects settings, etc. you see within Illustrator refer directly to how Illustrator will handle its own raster content when you ask it to create something like a drop shadow or a glow. It does not refer to placed images. What this means is any placed raster image is placed at its existing Pixels Per Inch (PPI). Illustrator does not alter raster image PPI. Therefore an image with a low PPI will place as a larger file (width and height). And an image with a higher PPI will place as a smaller file (width and height).

Traditionally with print design file sizes (kb) are unimportant. Can I ask why you are eyeballing the file size so closely? It's very, very common for files to increase to hundreds of MB or a few GB in some cases. This is the nature of print design where resolutions need to be much higher than on-screen work. When designing for print, you need to watch image quality and resolutions. Print design should never be about file sizes (kb).

Answer 2

The reason your files are getting smaller is because you are saving them at 180 DPI. Illustrator runs at 300 DPI consistently. So when you open it in illustrator it is going to automatically resize your file to 300 DPI. Which will, in turn make it smaller. Do this test in photshop. Open your file and click image and scroll down to image size. While in image size turn off scale styles and constrain proportion and resample. Now change your file's DPI from 180 to 300... Keep an eye on your image size and you will see how the files dimensions will change. This is what Illustrator is doing to your file. So just save your file at 300 dpi. This will make the image a little blurry but it will keep your file size.

Just a tip! If you are going to be creating for print always start your file out at 300 DPI.

Also if you save your files as .eps files or even .pdf when you place them the file should not jump up in size. Unless you are dragging the files to the illustrator program and letting it open them. There is a difference between placing a file from the file drop down, and actually placing the file on the illustrator icon to let it open it for you.