Image up-sampling

[Norah]

Hi
This is my first post here, and I'm facing a small problem with the book I wish to print.

I wrote my first eBook which is about the program 3ds max. At first I started selling it as an eBook, but after some time I decided I would like to print it as a PDF book with Ceatespace.com. However, during the processes of having it printed, I discovered that all the images of the book do not meet the printing requirements, because the images have to be at least 300 dpi. Most of my images are not larger than 150 dpi because I use screen capturing to capture the images from the program. The problem I'm facing now is that I have more than 400 images in the book, which makes the re-capturing and re-editing process of all the images all over again very difficult.
My question is; Can you help me find a way to up-sample the images in a simple and easy way or to find any way to print my book with this low resolution?
Thank you

[HarryT]

Moved to the "Workshop" forum.

[RbnJrg]

Maybe you could use PhotoZoom:

http://www.benvista.com/photozoompro

[HarryT]

Most graphics programs will allow you to change the size of an image. Your requirements seems pretty straightforward: you want to double the linear dimensions of each image.

[Norah]

RbnJrg, thank you ...i will give it a try
HarryT, thank you for your reply...
but if i change the size of the images dose that change the resolution too?
i will check that with Snagit.

[rubeus]

That does not make sense. Information not being present cant be added by scaling up. Your photos might be bigger, but still do have a poor resolution.

[pdurrant]

Originally Posted by rubeus

That does not make sense. Information not being present cant be added by scaling up. Your photos might be bigger, but still do have a poor resolution.

That doesn't matter for screenshots, which these seem to be.

[HarryT]

Yes. As I said, if you simply want to double the pixel density in an image that's the same physical size, double the linear size of the image (in pixels) while leaving it the same physical size (in cm).

[dwig]

Originally Posted by HarryT

Yes. As I said, if you simply want to double the pixel density in an image that's the same physical size, double the linear size of the image (in pixels) while leaving it the same physical size (in cm).

... or keep the same pixels and simply reduce the physical size.

Digital images, in and of themselves, do not have PPI (Pixels Per Inch; DPI or Dots Per Inch is always a incorrect term to use when discussing digital images). They only have pixels. It is not until they are placed in a page layout application with a concept of a virtual inch, or when printed on a physical page, that they "acquire" a physical dimension that can be measured in inches and thus you can calculate a PPI value.

Many digital image formats have a metadata field where the creator application can insert a PPI value. This value has no real impact on the number of pixels and thus no effect on the quality of the image itself. It is merely a instruction to a page layout application which, if it chooses to, can set its placement size so that the image is scaled to that PPI by default. If you scale the image in the layout application the PPI value is ignored and the true effective on paper PPI changes.

When a book is printed, the final effective PPI of an image is critical to getting good reproduction. Exactly what PPI is the best depends on the printing process. When the printing process uses halftone screens, the PPI needs to be a certain factor of the halftone screen frequency, 1.7-2.5x the screen frequency when using elliptical dot screens. Excessively high PPI actually lowers quality.

In the OP's situation, you need to first examine the final reproduction size of the images in inches. Only then can you begin to deal with how you resample the image to yield an appropriate PPI at that final size. You also need to be certain that the PDF generation tool doesn't further resample the images. If you are not using a true page layout application (Adobe InDesign, ...) but are, instead, merely converting an existing ebook, you need to review the settings in you conversion tool. You need to be certain that it resamples the images to the desired 300ppi value during the conversion, up-sampling or down-sampling as needed.

The final quality of the images will depend largely on the performance of the application doing the resampling. Screen captures can generally be upsampled a good bit and still look good if the resampling is done properly. The best results will generally be from using a good image processor (Photoshop, ...) to process the images to size and then building the master document in a good page layout application (InDesign, ...) without scaling the image in the layout program.

[DaleDe]

I would suggest IrfanView. It has a batch mode and can change the DPI and or resize the images as you desire. It has a resample function that can provide the illusion of higher density as well, scaling up or down. It is a great tool and is free. After it resizes everything you could easily take a look and redo any unacceptable images but nearly all or all will be fine.

Dale

[Norah]

Thank you all for your help,
All of the replies were very helpful to me,

Originally Posted by HarryT

Most graphics programs will allow you to change the size of an image. Your requirements seems pretty straightforward: you want to double the linear dimensions of each image.

Yes you are right, and I found a Photoshop tutorial which is simple way to increase the size, and I get reasonable results so far, h will keep playing with the settings until i get better results.
The method is explained in the following image

Originally Posted by RbnJrg

Maybe you could use PhotoZoom:

http://www.benvista.com/photozoompro

i tried to use this program but the result wasn't that good, may be i need to do more adjustment.

Originally Posted by DaleDe

I would suggest IrfanView. It has a batch mode and can change the DPI and or resize the images as you desire. It has a resample function that can provide the illusion of higher density as well, scaling up or down. It is a great tool and is free. After it resizes everything you could easily take a look and redo any unacceptable images but nearly all or all will be fine.

Dale

I will try this and see, thank you.

still the main problem is that i have huge number of images to correct, may be..when i start my next book... i have to consider the resolution earlier.

[DaleDe]

Originally Posted by Norah

I will try this and see, thank you.

still the main problem is that i have huge number of images to correct, may be..when i start my next book... i have to consider the resolution earlier.

that is why I mentioned IrfanView since it has a batch mode. You can let it do all the work.

Dale

[BetterRed]

Originally Posted by DaleDe

that is why I mentioned IrfanView since it has a batch mode. You can let it do all the work.

Dale

for Irfanview. It's my workhorse image manipulation tool, including its batch processing.

I also use imBatch from High Motion, it's also free. It can do some things Irfanview can't easily do - it's excellent for repeating batch operations involving a chain of transformations.

BR

[RbnJrg]

Originally Posted by Norah

i tried to use this program but the result wasn't that good, may be i need to do more adjustment.

Could you upload here one of the images that you want to resize?

[Norah]

Originally Posted by DaleDe

that is why I mentioned IrfanView since it has a batch mode. You can let it do all the work.

Dale

Yes you are right, but i am trying to install this program since yesterday and my win 10 keep preventing the installation due to some alert, i will try to fix it today and see.