My 300dpi image on a webpage becomes 200dpi when I use acrobat to capture it as a pdf. How can I preserve 300dpi?

[pjt11]

A 300dpi image on a webpage I created becomes less resolved, e.g., 200dpi, when I use acrobat to capture it as a pdf.

How can I preserve 300dpi (which I need for printing)?

[pjt11]

Correction: A 300ppi image on a webpage I created becomes less resolved, e.g., 200ppi, when I use acrobat to capture it as a pdf.

[Abambo]

On the web, the dpi value is nonsense. What counts is the XY resolution in pixels of the file.

In print, the dpi value (correct ppi) is a result of the size of the file in pixels and the reproduction size in cm/inches. The same file can be reproduced at a very small size (say 1 inch x 1 inch @ 300 ppi) or at a bigger size (say 2 inches x 2 inches @ 150 dpi) without changing physically anything to the file.

If you tell me the pixel size of your image, I can give you the maximal size in inches for a 300ppi file.

[pjt11]

Much thanks for taking the time to help.

The original image is 988 x 579 pixels in Photoshop saved at 300ppi.

The webpage specifies width 456px

When captured by acrobat, preflight says image is only 200ppi.

This is a test page. I have many more of them in the pdf I want to send to the printers.

[Abambo]

What is the size of the picture in cm or inches?

[pjt11]

The size on the printed page is 2.4 inches or 6cm wide.

[Test Screen Name]

Resolution (ppi) is absolutely irrelevant to the web page. And irrelevant in the PDF creation. What is the size in pixels or inches of the PDF image (in the PDF)?

[Test Screen Name]

Sorry, see you gave the size. If it were 988 pixels and 2.4 inches wide, it would be effectively 411 ppi. Not surprised to find it isn't preserved. HTML has no place whatever in making print-ready content. Don't do it that way.

[pjt11]

The size on the PDF is the same as the size on the printed page (given that they are both 8.5 x 11").

The original image is 988 x 579 pixels in Photoshop saved at 300ppi, and this means the image in photoshop is 3.3 x 1.9"

One test html file asks for the image to be 500px wide. Clearly that does NOT mean that the image on the webpage is 593ppi NOR that it comes out at 1.65" x .96" . But I did not expect the pdf captured from that web to be a lower quality (ppi) than the original.

Another test html file does not specify the size of the image and it comes out around 2.4" wide.  This size mystifies me, but I could live with it EXCEPT again I did not expect the pdf captured from that web to be a lower quality (ppi) than the original.

Help to understand what is going on is still sought.  Thanks.

[Of course, I could avoid this problem is I transferred into a word file all of the c. 200 webpages being assembled into this publication, then worked from word (where image resolution in the resulting pdf is equal to that in the word file). BUT I would love to understand what is going on before taking on this HUGE job of copying, pasting, and reformatting.  (If you think I should just do that, no need to contribute to the thread.)]

[Abambo]

Short calculation: 579/2.4" = 241.24 ppi.

On the webpage, resolution is measured in pixels. Screen resolution has been arbitrarily fixed at 72dpi (there is some sense behind, but at today's standards it may be more than obsolete).

Going from print quality to a web page to print quality is not the way it should be worked out.

One test html file asks for the image to be 500px wide. Clearly that does NOT mean that the image on the webpage is 593ppi NOR that it comes out at 1.65" x .96" . But I did not expect the pdf captured from that web to be a lower quality (ppi) than the original.

500px wide does mean 2 things: Either pictures get downsampled to 500px (500px/2.4=208ppi) or the picture gets squeezed to 500px. I do not know what happens when I convert now that web page to pdf.  I would guess to get a pictures of 6.9".

The big problem here is probably that you did not explain what you really do or intend to do.

The resolution of any picture is expressed in pixels. So if you do not touch the pixels, you do not touch the resolution. If you touch the ppi at the same resolution, you are modifying the density of the pixels. The higher the density, the smaller the size and vice versa.

[pjt11]

Thanks for your continued input.

What I am trying to do is take an image that is 300ppi or denser, include it in a webpage, capture that webpage using acrobat into a pdf and having preflight show that the image is still 300ppi or denser. (Printers such as Lightning Source require 300ppi or better.)

At the moment, my images get preflighted as less than 300ppi and I don't understand how to prevent that.

[Abambo]

The web is not done in that way and has no idea about ppi.

How do you convert your pictures from the web to PDF? What are your parameters?

The printer does not require 300ppi but quality will degrade if the density is much less. You see that very often, when people are using highly compressed and optimized pictures from the web for print.

Your web sites, are that standard public websites or are you creating those just to get the PDF file? In the first case you do not have control over the pictures in the second case it will be a nonsense work flow.

[pjt11]

I have two workarounds:

1. Submit the pdf to printers, which they accept even though images are below 300ppi, and it comes out OK.

2. Use acrobat to convert pdf to word, then replace images with 300ppi versions. Finally, save as pdf and submit to printers. (This is less time consuming than copying and pasting each webpage over to word and preparing manuscript in word.)

Despite explanations given in this thread, I still don't understand what happened that reduced the ppi.

[Test Screen Name]

It happens because you want the software to care about something that's important to your workflow, but which is entirely outside software developer's aims and intentions. As I have said: starting with HTML when you want to get quality printing is the wrong path, the part you need to change. But I know what it's like when you've invested time and energy in a particular path.

My suggestion would be to make it in Word, if you don't have design software. You might even be able to start by opening the HTML in Word.