TIFF to JPEG

<p>A friend just sent me a photo saved as a TIFF that was 16.4 MB. I loaded it into Lightroom then immediately exported it at 100% to a JPEG and it is now 1.6 MB. Should this be higher? IS there a better way to save this to get it to be a higher resolution? I know the RAW file was 19.4 MB and when saved as a JPEG it went to 7 MB.</p>

<p>Thanks</p>

<p>Preston, a JPEG file is much lower quality than a TIFF file (given the same image). Data is lost when converting it, so the file should be smaller. On top of that, JPEG is only 8 bit, and if the TIFF was 16 bit, then immediately you lose half the file size. TIFF is also a text file representation of your image, so it will be much larger than an encoded format, like JPEG or Photoshop.</p>

<p>MB (<strong>file size</strong> in Mega Bytes) do not equal DPI (<strong>resolution</strong> in dots per inch) - there is no direct correlation. It is true that <em>all else being equal</em> a high resolution image will be a bigger file size (more MB) than a smaller resolution image. But the difference between TIFF and JPG is not resolution, it's file data. Again, all else being equal, a TIFF file will be bigger than a JPG file of the same image. When you save a TIFF file as a JPEG you are throwing out data to make a smaller size file. (though if you save a JPEG as a TIFF it will get bigger - not because it's increasing the amount of data in your image file, but because a TIFF file saves what it knows in a bigger package, so to speak. It stores what it knows about your image in such a way that it can get to all the data again without trashing anything.) If you want the most data (information) possible, don't save it as a JPEG. </p>

<p>You would get a lot of good out of reading a primer on file formats, resolution and camera RAW - I don't know where they'd be on this site, but I'm sure somebody on photo.net has covered this stuff.....</p>

<p>Sounds about OK to me. For 12 megapixel image, I get a 35MB TIFF, 8-bits, without compression; so 16.4 sounds around 5 to 6 megapixel, 8-bits TIFF. JPEG size sounds accordingly, slightly smallish, but JPEG compression ratios can be quite high depending on the picture. Without seeing it, that's a bit harder to judge.</p>

<p>Let's also be clear that DPI settings (as see in the JPG file) also have nothing to do with resolution. Only the actual number of pixels (wide, and tall) matter when it comes to the size/complexity of the image.<br /><br />And pretty much any piece of software that can create a JPG file (even from a different JPG file) includes a control, during the "save" process, that lets you indicate how aggressively you want to compress the file. This comes at the expense of visible detail and smoothness of gradients, of course. But even a modest increase in the compression setting can drastically reduce the size of the saved JPG file.</p>

<p>When you exported it from Lightroom at 100%, what was your jpeg quality setting? That would affect your file size too (but not resolution), and you might be compromising the file more than you intend to by saving it at a low quality setting.</p>

<p>Peter</p>

<p>When you exported it, did you resize it (option in the export dialog box)?</p>

<p>IMO in general stay away from jpg until you have a final version of a photo, then it is OK to use jpg. For web use it is almost required to convert to jpg, and a lot of consumer print labs want jpg as well.</p>

<blockquote>

<p>A friend just sent me a photo saved as a TIFF that was 16.4 MB. I loaded it into Lightroom then immediately exported it at 100% to a JPEG and it is now 1.6 MB. Should this be higher? IS there a better way to save this to get it to be a higher resolution? I know the RAW file was 19.4 MB and when saved as a JPEG it went to 7 MB.</p>

</blockquote>

<p>I am confused. You have a 16.4MB tif file that started out as 19.4MB raw file? If so, your original tif file was a severley cropped version of the original. So, saving the 16.4MB tif at 100% jpg your 1.6MB might not be too far off.</p>