Adoramapix help

I have been using costco for the last year for printing my 11x14 images. I am using a 300D so the files are approx 2664x2048. I have just been sending them in with no correction done by costco.

Now I wanted to see what the kodak metallic looks like so I sent some to adoramapix.com. I took me to a section with a bar that showed that my image quality was in the middle. 300 DPI being best and 100 DPI at minimal. So I took the same image, and set the resolution in photoshop to 300 DPI which of course greatly increased the size of the image. And then the bar graph was at the top of the quality chart.

The question is, I have been selling my images like hotcakes and was very impressed with the quality of costco. I have a friend who was printing out images for me on a Canon Pro 9000 and the quality of that and costco was the same. I am wondering if the images that I have been sending to costco needed to be set at 300 DPI before sending them?

jtack wrote in post #10538021
I have been using costco for the last year for printing my 11x14 images. I am using a 300D so the files are approx 2664x2048. I have just been sending them in with no correction done by costco.

Now I wanted to see what the kodak metallic looks like so I sent some to adoramapix.com. I took me to a section with a bar that showed that my image quality was in the middle. 300 DPI being best and 100 DPI at minimal. So I took the same image, and set the resolution in photoshop to 300 DPI which of course greatly increased the size of the image. And then the bar graph was at the top of the quality chart.

The question is, I have been selling my images like hotcakes and was very impressed with the quality of costco. I have a friend who was printing out images for me on a Canon Pro 9000 and the quality of that and costco was the same. I am wondering if the images that I have been sending to costco needed to be set at 300 DPI before sending them?

By upscaling them to 300dpi you did nothing but increase your file size.

Sdiver2489 wrote in post #10538064
By upscaling them to 300dpi you did nothing but increase your file size.

I knew that as well. The original image was 2609x2048 and I have sent that to costco and printed out at 11x14 flawless results and also at 16x20 with no negative IQ. Then I sent the same file to adoramapix.com and it said that my IQ was in the middle between optimum and low. Then I pumped up the DPI to 300 which brought the image to 4348x3413 and the bar jumped up high quality. But I fail to see how those two images would be any different IQ wise.

jtack wrote in post #10538153
I knew that as well. The original image was 2609x2048 and I have sent that to costco and printed out at 11x14 flawless results and also at 16x20 with no negative IQ. Then I sent the same file to adoramapix.com and it said that my IQ was in the middle between optimum and low. Then I pumped up the DPI to 300 which brought the image to 4348x3413 and the bar jumped up high quality. But I fail to see how those two images would be any different IQ wise.

You aren't understanding what they are doing. They are simply looking at resolution per size. The "golden" standard is 300 dpi. Your original image did not meet this so they don't define it as "perfect quality". Is it good enough for most people? Yes.

When you increased your image resolution artificially, adoramapix has no way of knowing that this wasn't the native resolution of your image. So when they see it meets 300dpi then they report it as being ideal. The quality, however, will be no better than the original image.

Perfect, that's what I wanted to know. Thank you! So, I guess it is safe to say that taking the picture with a higher MP camera would be the correct way to achieve the "golden" standard for 300 DPI for an 11x14 image.

jtack wrote in post #10538769
Perfect, that's what I wanted to know. Thank you! So, I guess it is safe to say that taking the picture with a higher MP camera would be the correct way to achieve the "golden" standard for 300 DPI for an 11x14 image.

Yes but it really is unneeded. 300dpi is overrated in my opinion

Sdiver2489 wrote in post #10538827
Yes but it really is unneeded. 300dpi is overrated in my opinion

so what is minimum acceptable dpi?

Well I've printed at 187 dpi and been perfectly satisfied. I imagine opinions will vary wildly on this topic though. When you get up into prints that are 16 x 24 and larger it gets very difficult to meet the 300dpi rule.

My feelings are similar to TV sizes. Resolution is a function of how close it will be inspected. Smaller prints will likely be closer to your viewer so a higher dpi is probably a good thing. Larger prints will generally be viewed from a few feet back which demands less resolution. Same reason why people use to suggest getting a 720p TV and saving money vs a 1080p TV. When you view it from normal distances, its really tough to tell the difference.

Sdiver2489 wrote in post #10538894
Well I've printed at 187 dpi and been perfectly satisfied. I imagine opinions will vary wildly on this topic though. When you get up into prints that are 16 x 24 and larger it gets very difficult to meet the 300dpi rule.

My feelings are similar to TV sizes. Resolution is a function of how close it will be inspected. Smaller prints will likely be closer to your viewer so a higher dpi is probably a good thing. Larger prints will generally be viewed from a few feet back which demands less resolution. Same reason why people use to suggest getting a 720p TV and saving money vs a 1080p TV. When you view it from normal distances, its really tough to tell the difference.

yeah thank you..I only have printed once, a 8x12 and 4x6, I did use 300dpi on both... coz I thought it was ideal I might print a bigger 20x30 next month. so its not really necessary to use 300dpi all the time. thanks

1) There are many different methods used to interpolate extra pixels in an image. Spline, fractal, wavelet, and others. Different images will look best when interpolated using different algorithms. (You can get applications and Photoshop plug-ins to use these different algorithms to interpolate pixels in digital images.) Following interpolation, smoothing or sharpening may improve the final result. Therefore, when you upscale the number of pixels yourself, you can in theory get a better result than letting Adoramapix or someone else do it for you.

2) The necessary resolution decreases in proportion to viewing distance due to the acuity of the human eye. Many sites indicate 300 dpi corresponds to 20/20 vision at 8-11 inches. (Many people see better than this and some people can have up to double this visual acuity.) Usually viewing distance is estimated at 1.5x the diagonal of the print. However people can inspect a large print closely. Also, the chemical minilabs at many printers print at resolutions of 300x300 or 300x600. If you provide smaller resolutions, the software will have to interpolate the pixels up to this level, reducing your control of the final image. On the other hand, if the viewing distance is large, this interpolation won't be visible anyway.