Image DPI 1

[cricketx]

Ok.......so I got some pictures of the internet and now my printer says that they are all 75DPI's in the pdf I created and won't look good when printed through press.

They look decent when I view them on screen and I am using the press style to export to pdf. Any ideas?

Is there a software which can tell me what DPI the images are?

Indesign2
Windows XP (SP1)
Designing Tabloid Newspaper (Any tips welcome)

 

[Genimuse]

He's right, unless you reduce the size quite a bit, they won't look good. Your screen is fooling you.

To get a good looking picture once the printer (imagesetter or other printing device) creates the screen, you need to have roughly 150% to 200% of your line screen in dpi.

For example, in a tabloid newspaper the line screen will probably be around 85lpi to 100lpi (ask your printer what the line screen will be). That means if the lpi (lines per inch) are 85 then you'll need pictures that are between 128dpi and 170dpi, and if the lpi is 100 then you'll need pictures that are between 150dpi and 200dpi. Any lower than that and the pictures will look jaggy and blurry.

Note that the dpi in question is the dpi after resizing the image. For example if you have a 150dpi image and you blow it up to twice its size in InDesign then you really now have a 75dpi image (half of 150). If, on the other hand, you shrink it down to half its size in InDesign then you now have a 300dpi image (double 150).

Almost any image editing program (such as Photoshop) will give you the dpi of the image.

Note that you are almost undoubtedly violating copyright if you retrieved the images from the web, taking advantage of someone else's hard work without compensating them at all. You might consider if you would like the same done with your hard work. Clip art and clip photography is so stunningly inexpensive these days, it's a shame to not pay someone for the effort, in my opinion.

 

[cricketx]

ok i kinda understand. I have photoshop but cannot find the right setting to check dpi. Can u point me to the right setting?

---
I knew while posting that it may sound dodgy that I am taking pictures from the web.
We _always_ take permission before using someone else's work and understand how copyright works.
---

BTW, Not all pictures were from the web. Some were in MSWord which I copied and then pasted into the layout. Is any quality lost during copy and paste?



Indesign2
Windows XP (SP1)
Designing Tabloid Newspaper (Any tips welcome)

 

[jimoblak]

Photoshop dpi : Image Menu>Image Size

Please take this as constructive advice and not an insult... By getting images from the internet and other MS Word documents, you appear to be oblivious to basic matters of color models (CMYK v. RGB) and resolution. I would recommend reading up on this. A good place to start is about.com with keyword 'desktop publishing'



- - picklefish - -

 

[Genimuse]

An important thing about using Image Size in Photoshop (or any other photo editor): Changing the dpi while resampling (with the Resample checkbox turned on) doesn't necessarily solve your problem. Photoshop will do its best to add in new pixels between the old one, interpolating (calculating an average) to increase the dpi.

If you're increasing dpi without decreasing size this will help the jaggies a bit (but won't solve them), and will do nothing to fix the blurriness you'll get with too-few dpi. Basically if the data/detail isn't there, it simply isn't there.

On the copyright issue: that's great, glad to hear it. I didn't mean to preach so much as inform.

On the color issue, jimoblak is absolutely right, and you may well have color separation issues when it's time to print. Even if you don't (that is, InDesign or the PDF RIP takes care of the conversion), you won't end up with the colors you expect and the pictures may look muddy or dull.

Ideally you'd convert all of the RGB images to CMYK (in Photoshop Image Menu->Mode->CMYK) and will use a profile for the conversion that matches the press it will be printed on. This issue gets a lot more complicated as printer and monitor calibration come into play, so I can't explain it all here. Definitely check out jimoblak's suggestion.

 

[cricketx]

yeah thanks for the reply.......I know that all pictures should be in CMYK and printer is happy wif the conversions. The pictures I got from the word doc will be printed in grayscale so its not a prob.

I finally got some high resolution pictures but they are still in jpg format and when i open them in Photoshop, it reports a ppi of 72 but they are really huge. (Actually it reports that for all images I try)

Now my questions: If I reduce it to 1/4 the original size and use "fit content proportionally" in indesign2 will that increase its ppi (and i presume dpi).



Indesign2
Windows XP (SP1)
Designing Tabloid Newspaper (Any tips welcome)

 

[jimoblak]

If you use the Image>Image Size in Photoshop, you will see that you can set the DPI to 300 and the physical dimensions will shrink. (be sure to uncheck the resample image box)

This modification will only illustrate how the dpi and physical dimensions relate to each other. You do not need to redefine the dpi and physical dimensions of your new larger images. The new images can be placed in InDesign and scaled down there.

- - picklefish - -

 

[Genimuse]

Pre-InDesign (with QXP or PM) it was always better to set final physical size and resolution in Photoshop first because (a) it used bicubic interpolation to process the pixel changes rather than letting the imagesetter do a poor job of it, (b) after removing information it was often best to perform a bit of Unsharp Mask-ing to bring back a little edge definition lost in the process, and (c) there was no need to store all that extra data and transmit it everywhere.

Has any of this changed with InDesign in some way? I know that point (c) can be addressed by letting the application downsample when a PDF is generated, but ye gads, that seems like as bad an idea as having the imagesetter do it.

Any thoughts?

 

[jimoblak]

I was always cognizant of saving images in the right scale and angle when using PM so that I would not have to send a document with 20 CDs worth of linked images. I now find myself sending everything to my printer as PDF so the PDF downsampling suits my own situation. If you have plenty of storage capacity and processing oomph when distilling PDF, using a 24 Mb file for a tiny 1"-square image is not a concern. It may actually save space since you do not need to make copies of your images in so many smaller resolutions.

I may better prepare my images (points 'a' and 'b') for high quality work but I can't recall the last time I ever did anything high quality.

- - picklefish - -

 

[Mattblack]

I must agree with Jimoblak on this. I used to send a certain document to print direct from PM that ended up at over 1 Gig as a print file. I now generate print resolution PDF files from Indy, and the size at the print stage is reduced to 200Mb. The quality is just as good, the ripping time is reduced, and my PC is not tied up.

I am a definite convert to the PDF file.