Smaller file sizes in ACR from DPP?

I am confused about something thats going on here. I am using a Canon 50D and shooting in RAW. When I open a photo from my card in Adobe Bridge to ACR in CS3, My file sizes are smaller than when I use DPP. Example: I view contents of card on Bridge, double click the thumbnail and it opens in ACR. I process in ACR then hit open image. The Image opens in CS3 as a TIF file. Check file size and it is 4752x3168 with a resolution of 240, 41.3 MB. If I open the same image from the card in DPP and process, convert and save as a TIF file, then open in CS3, image size is 4752x3168, reslution of 350, 86.1 MB. Can someone explain this? Am I doing something wrong and could it have an impact on my photos?
Thanks
Clayton

I don't know DPP for XYZ, but I'm betting that it's opening the files as 16 bit while your ACR is opening them as 8 bit. That would account for the approximate doubling.

Thanks Hank.
I checked and that is whats happening. I'm still not positive if and how it might affect my final images. I would think it would have some impact on any final processing I do in CS3. Is there a setting in ACR that would convert to 16 bit as apposed to 8 bit?

Within CS3 you can go to Image->Mode and select 16 bit rather than 8 bit once an image is imported, but if you're opening it from DPP right into CS3, I'm betting the adjustment is in DPP. I'd look under Preferences first, but it could well be elsewhere like Color or some such. Someone familiar with DPP shoud speak up I think.

Hank is referring to getting 16-bit from DPP into CS3, but I think you asked about going from ACR into CS3. In ACR there is a text link "button" at the bottom of your image that specifies the output type and parameters. You can click on it to change it, and that should let you setup 16-bit output to CS3.

Thanks David. I found it. My images still show a resolution of 240 instead of 350 however.

That's not a measure of resolution Clayton. All that is is a piece of metadata, just like the lens used, or your name or info. It can be changed at any time without actually changing the photo contents of the file. Change it to anything you like, and the file will be the same size and exact same appearance (i.e. have the same resolution). (Be careful not to let the software resample if you change it - resampling WILL change the contents of the file.) If you want it to be 350, you can set that as the default in ACR settings.

For lots more on the ppi, exactly what it defines, when it's used, and how it's mis-used, please see this forum discussion :"DPI doesn't matter"