Is a larger pixel dimension/width or height better than Resolution on image sizing?

[tara_ratliff]

<p>If you have a 5 x7 width or height, and 720 resolution which is the highest it will go from RAW on my set up, would it be better to do 360 resolution and have a bigger width and height when editing from raw? I don't know if this question is confusing, but if someone is going to print an 16x20 is it better to edit at the 5x7 with resolution 720 or start off with a bigger image size and do 360 and then change the resolution to 720 later?</p>

[john_a5]

<p>In a sense, your question is sort of irrelevant as each is dependent on the other and if you "retain" the maximum number of pixels, nothing is gained or lost. For instance, an image at 4x6 at 900dpi is no better a starting point than a 36x54 inch image at 100dpi, each is 3600x5400pixels. Neither is affecting the quality of the image one way or the other. If you decide later to print, by uprezing, an image at 12x18@360dpi, starting at either of these settings will yield the same result if you uprez by the same procedure.</p>

<p>So, the answer is essentially, it doesn't matter.</p>

[chas_frady]

<p>Are you talking about DPI or PPI? If PPI, as in the settings from Adobe Camera Raw, it makes no difference unless you are going to print. Pixel dimensions are all that's relevant here. Just leave the dimensions at the native size that came from your camera.</p>

[Tim_Lookingbill]

<p>Forget all the resolution stuff when printing to outside vendors. Your camera gives you all it's got shooting Raw in resolution and color.</p>

<p>You have no control over what a third party printer does with resolution when printing. These printers use their own proprietary resampling algorithm that's usually quite superior to what can be done in Photoshop or any other image editor.</p>

<p>Jeff Schewe, a very well respected and published photographer and digital imaging expert, suggests just setting your print size in inches in Photoshop's "Image Size..." dialog box and uncheck resample and save the file in your format of choice. This is just a precaution and doesn't necessarily influence what the third party printer's algorithm will do to the file once printed.</p>

<p>But it doesn't hurt and gives piece of mind when the results don't look right on the printer's end of the deal.</p>

<p>Frankly all this resolution concerns shouldn't be an issue anymore considering the majority of modern camera's deliver plenty of resolution for any printer's algorithm to print satisfactory results.</p>

<p>Remember the bigger the print the farther away you have to view it. The farther away you have to view it the less you'll see any noticeable artifacts which most of the time can't be seen from one foot away. </p>

<p>Just make sure it looks the way you want at 50% to 100% zoom view in your image editor of choice.</p>

[jacopo_brembati]

<blockquote>

<p>These printers use their own proprietary resampling algorithm that's usually quite superior to what can be done in Photoshop or any other image editor.</p>

 

</blockquote>

<p>Nearest neighbor LOL</p>

<p>Jacopo</p>

[jacopo_brembati]

<blockquote>

<p>Jeff Schewe, a very well respected and published photographer and digital imaging expert, suggests just setting your print size in inches in Photoshop's "Image Size..." dialog box and uncheck resample and save the file in your format of choice.</p>

</blockquote>

<p>In this way you get <strong>exactly </strong>the same image LOL</p>

 

[Tim_Lookingbill]

<p>jacopo, what's so funny?</p>

<p>What's nearest neighbor have to do with third party printers?</p>

<p>The last comment is obvious, but don't see anything funny about it. </p>

<p>Got something on your mind?</p>

<p>You know I proved this works with a local minilab. Couldn't see any improvement or difference to the final print resolution on a 6MP image enlarged to a 16x20 inch print.</p>

 

[jacopo_brembati]

<p>Nearest neighbor is the worst resampling algorithm and it is generally used from printers drivers.<br>

This is the <strong>superior proprietary resampling algorithm</strong>.</p>

<p>Image size is untouched if you change the ppi value without resampling.<br>

The suggestion for a null operation is completely unuseful.<br>

It's funny you can get this suggestion from a <strong>digital imaging expert.</strong></p>

 

[szrimaging]

<p>Jacopo, you should try dealing with writers for magazines sometime. I work at a resort and the freak out when they open the file and it doesn't say 300dpi, even though the pixel dimension is whatever you get out of a 10MP camera (or above) and the print is going to be less than 4 inches on the page. It is seriously sad that people who deal with this for a living don't even understand all of this.</p>

[jacopo_brembati]

<p>Zach,<br>

I try to explain that ppi doesn't make sense before you fix the print size at any time.<br>

I educated many people to understand this. But I know there are many people that don't know this elementary concept of digital imaging.</p>

<p>I agree:</p>

<blockquote>

<p>It is seriously sad that people who deal with this for a living don't even understand all of this.</p>

</blockquote>

<p>I will continue to try to explain and I hope <strong>experts</strong> stop to diffuse misinformation.</p>

[Tim_Lookingbill]

<p>Scroll down to what Ellis Veneer says what Jeff Schewe said on this thread:</p>

<p>http://www.photo.net/digital-darkroom-forum/00RajR</p>

<p>I might have misquoted him about the 180 ppi and turning resampling off.</p>

<p>Frankly I think you're splitting hairs on this, jacopo. My main point is to not sweat it by trying to control this on the user's end because no one knows absolutely what the outside third party printer is going to do to an already upsampled file.</p>

<p>Do you mind supplying proof that all third party printers use nearest neighbor as their uprezzing/resampling algorithm?</p>

<p>And just FYI, I'm not a paid professional and try as hard as I can to remember all this complexity concerning resolution. So excuse me for my bad memory.</p>

<p>Note how confusing that thread got into the subject. You want a good laugh? Laugh it up!</p>

[jacopo_brembati]

<blockquote></blockquote>

<p>Quote:</p>

<blockquote>

<p>According to Jeff Schewe, Greg Gorman ,and Mac Holbert at the Epson Print Academy seminar a couple of weeks ago:<br />You should be fine by not resampling your images as long as the file you send it has greater than 180ppi resolution.<br />So, open the photo in Photoshop (you are working in PsCS3 as I recall). Go Image >image Size and turn off (by unchecking) Resample Photo. this links the Width, Height and Resolution settings in Document Size.<br />Now adjust the height or width to the size you want and as long as the Resolution is above 180 pixels/inch you should not see a reduction in image quality. Even the representative from Genuine Fractals parent company acknowledged this. But if f you go below 180 then that is the time to employ Genuine Fractals or other methods of resolution interpolation.<br />Now turn the Resample Image tool back on.<br /><br /></p>

</blockquote>

<p>180 is not a magic number.<br />Epson drivers work at 720/360 depending on models and quality setting (for "no borders" prints the values are slightly increased).<br />So 180=720/4 (or 180=360/2).<br />In that case, the driver uses each pixel 2 (or 4) times.<br />Generally this is not dramatic as the driver resampling uses pixels in a symmetric way.<br />If you have more than 180 ppi and less than 360 ppi, the resampling ratio is lower but asymmetric.<br /><br />Is the effect visible on printers? It depends. But if you have subtile geometrical patterns you can see the difference.<br /><br />If you print on Canon or HP things go different.<br />Canon and HP work at 600 ppi (high quality), so 300 (or 150) may be a good value, 180 is not a good value.<br /><br />If a lab generates your prints the 180 rule is again breaked.<br /><br />Resuming all:<br /> 1- the best thing to do before printing is a resampling (with an optimum algorithm) to the ppi value required from the printer driver<br /> 2- resampling to ppi/2 or ppi/4 may be acceptable<br /> 3- resampling to any other value results in a worse print<br /><br /><br />There is another point to explain to avoid confusion:<br />Image file as tif or jpg or png have a ppi information.<br />This information is a nonsense as ppi may be computed only when you fix the print size and print.<br />This information is completely ignored from the printer driver, instead ppi value is computed on fly starting from image pixel dimensions.<br /><br />Image has not physical size until you render it.<br />So changing ppi value in the image container makes "nothing" (read Zach post).<br /><br />I'm trying to explain how a printer driver works and there is no any personal attach. <br /><br /></p>

[Tim_Lookingbill]

<p>Yeah, I get what you're saying, jacopo.</p>

<p>This page shows how Canon, HP and Epson differ in rendering stochastic dithering:</p>

<p>http://www.silverace.com/dottyspotty/issue3.jpg</p>

<p>This dithered dot technique in rendering pixel data shown in that sample has its own resolution that doesn't line up to pixel resolution with regards to when you start seeing stair stepping along edges and fine lines. Different brand printers will have their own threshold which never relates to true resolution either from the pixel pattern or the dither pattern.</p>

<p>When you don't know the printer being used like in the case of a wedding photographer submitting jpegs on CD's for their clients to print from, all that in depth knowledge is pretty much useless.</p>

<p>If wanting the highest split hair quality, then you have to do tests when sending to outside vendors. </p>