Resolution for professional printing

[mal1e]

I am self publishing a book and have some questions regarding the resolution of graphics needed for the professional printer and the steps to increase the resolution for the cover shot.

The graphics on all of the inside pages are a minimum of 300 dpi, in CMYK format.

However, I remember hearing the cover shot has to be a higher resolution. Is this true?

My cover shot was the only photo that was too small. It was 588kb and needed to be enlarged. Doing so would decrease the resolution, so I needed to increase the resolution, both because it is the cover shot and because it needs to be enlarged.

Here is what I did. Please tell me if there is anything wrong with what I did:

In Photoshop, I went to Image, Image Size. Then I simply increased the resolution from 300 to 600 dpi with the two boxes, Constrain Proportions and Resample Image, checked. The quality of the photo seemed to be undiminished. The biggest problem this caused is that the file size increased to 68 MB. The cover is the only page in the book that is/will be a JPEG, placed as a single graphic onto Adobe Indesign. I have not placed the cover shot in Adobe Indesign yet, for fear that it will crash the program.

I wanted to give a draft of the book, as a PDF, to a friend. I turned the inside pages into a PDF document. Then I turned the cover page (the photoshop graphic) into a PDF and combined the two. Then when I tried reducing the file size in Adobe Acrobat, the program kept crashing. I think it was because the combined file was more than 50 MB. This is why I have not placed the cover shot in the Adobe Indesign file yet.

[jerryb]

hi,
now i am sort of a novice.... but if i want to increase both the dpi and the pixal deminsions.. this is the procedure i use....
1. go to your image size....
2. uncheck "resample" the put in the dpi setting you want...!!
3. at this pint your files size hasn't changed.....
4. i then will then recheck "resample"
5. i generally choose bicubic sharper... but try both bicubic sharper or bicubic smoother... pick what ever works best for you...
5. then I plug in the new "document size" or pixal size i want....! at this pint file size will change.. over all the quality should be fairly good...

the results are pretty good

I am self publishing a book and have some questions regarding the resolution of graphics needed for the professional printer and the steps to increase the resolution for the cover shot.

The graphics on all of the inside pages are a minimum of 300 dpi, in CMYK format.

However, I remember hearing the cover shot has to be a higher resolution. Is this true?

My cover shot was the only photo that was too small. It was 588kb and needed to be enlarged. Doing so would decrease the resolution, so I needed to increase the resolution, both because it is the cover shot and because it needs to be enlarged.

Here is what I did. Please tell me if there is anything wrong with what I did:

In Photoshop, I went to Image, Image Size. Then I simply increased the resolution from 300 to 600 dpi with the two boxes, Constrain Proportions and Resample Image, checked. The quality of the photo seemed to be undiminished. The biggest problem this caused is that the file size increased to 68 MB. The cover is the only page in the book that is/will be a JPEG, placed as a single graphic onto Adobe Indesign. I have not placed the cover shot in Adobe Indesign yet, for fear that it will crash the program.

I wanted to give a draft of the book, as a PDF, to a friend. I turned the inside pages into a PDF document. Then I turned the cover page (the photoshop graphic) into a PDF and combined the two. Then when I tried reducing the file size in Adobe Acrobat, the program kept crashing. I think it was because the combined file was more than 50 MB. This is why I have not placed the cover shot in the Adobe Indesign file yet.

[rachjm]

However, I remember hearing the cover shot has to be a higher resolution. Is this true?

I have never heard of this - 300dpi is normally perfectly adequate for printing. Before you do anything else, you should contact your printer and find out the facts - you could be wasting your time with all of this image resampling.

The process that you have described is correct - it's really the only way to 'increase' resolution. Such a huge file size is to be expected with a large image at 600dpi, and it is almost certainly this that is causing Acrobat to crash - I would recommend sending the image to your printer separately without exporting to PDF (exporting will only reduce the quality of your image, anyway).

For the purposes of sending a draft to your friend, you'd be better to make a copy of the cover image that has been down-scaled and optimised for screen viewing - your friend certainly doesn't need to preview the cover at 600dpi!

[Medley]

A lot is going to depend on what type of printer you're going to use. Inkjet prints require a different setup than half-tone prints. Even the brand can make a difference in inkjets- I prepare prints for Epson printers differently than most other inkjets.

If you're using an inkjet printer, then you're wasting your time resizing the cover image- the printer is going to resize it again to it's own specs anyway.

- Joe U.

[mal1e]

If what I did is the correct method to increase resolution, why is everyone told there is no way to increase resolution? On this message board and others, people have asked the same question and have been told there is no way to increase the resolution without damaging the quality of the photo.

[jerryb]

hi,
it is a confusing issue..... smmile and like I said i'm just a novice....
but my thoughts...
1. you can increase or decrease resolution in itself.... that not a issue... however doing that you add or remove pixals.... that does change the quality...!!! and how much quality is losed depends on how much is added and the meathod or program that used (primnarily how good the alogrythems that used)

2. now when you change the dpi to a higher number..using photoshop .... if you have resample unchecked... whatt take place is no pixarls are added! ... the document size will get smaller because you putting the pixals closer together but no quality is lost! ....... however if you check marked resample and put in your dpi ...... the document size will remain the same and pixals are added in order to maintain the document size!! and that will effect quality..also you'll end up witha bigger file size ...

I hope i said it correctly and it understandable.... there was good video tutorial by mark wilson a while back on there radiant website but it no longer there.. he said it much better than me...!!

If what I did is the correct method to increase resolution, why is everyone told there is no way to increase resolution? On this message board and others, people have asked the same question and have been told there is no way to increase the resolution without damaging the quality of the photo.

[rachjm]

If what I did is the correct method to increase resolution, why is everyone told there is no way to increase resolution? On this message board and others, people have asked the same question and have been told there is no way to increase the resolution without damaging the quality of the photo.

They are right - there are some pretty good plugins out there, but there is still no fool-proof way to increase the size of your pic without quality loss. In your case, with your book cover - you've already got it at 300dpi. Your eye probably won't notice the quality loss between that and 600 because 300 is already pretty high. And on-screen you're probably viewing at less than 8% to get the whole image in anyway...

Just to clarify, are you printing this at home or with a professional printer? If you're getting it done professionally, what printing method will they be using for the cover? (i.e. Offset/digital?) Because if it's a digital print you could easily ask for a proof at 300dpi and another at 600 - then you can see for yourself which one looks best...

[mal1e]

Actually, what I wanted to do was enlarge the photo so that it could be placed on the cover, however by doing so the dpi decreases. That is why I increased the dpi. So that at the size I needed it, it would be a minimum of 300 dpi still.

I'll find out if the professional printer I will be using uses digital of offset printing. Thanks for your help.

[Etheryte]

Are you sure you need to enlarge the dpi? My guess would be, that the printshop needs the image in larger proportions, not dpi, for bleed edge.