Tag: Photoshop

Image Resolution in Reproduction

Image Resolution in Reproduction. How big can it go?

Today cameras are everywhere. Almost every phone offered today includes a high quality camera built in them. From selfies to family portraits or even just a quick snapshot of your beloved pet can produce that one photograph you would just love to have blown up. But how big can it go? Image Resolution in regards to Reproduction is key.

For the sake of our readers I will forgo taking a selfie and just use an example image at a resolution with an approximation of a 16M camera phone photograph (5312×2988). Let us use this image of the Louvre.


Image Size Dialog

In Photoshop we can pull up the Image Size Dialog (alt+control+i on pc or command+Option+i on a mac) to see that our photo is a decent size at 73.778″x41.5″ at 72 dpi. this can make for a excellent print, but at what size?

A good rule of thumb for standard photo viewing (2 feet or less) 300 dpi is more than acceptable, you can go higher if your image allows but keep in mind that at 10″ the average human eye in optimal viewing conditions cannot discern past 650 dpi. The further back your viewing distance the lower resolution can become acceptable. In the range of 5 to 10 feet 72 dpi is an acceptable resolution. Keep in mind these numbers are considered optimal for good lighting and weather conditions, low quality lighting and adverse weather will impair perception over distance.

If we do not plan on cropping our image we can do this directly from the Image size dialog, with one minor change. In the dialog there is a check box labeled “Resample Image”. While the algorithms for photo up-sampling are light years better then what they were years ago it still does not quite do the job for the quality outputs we are looking for, so we will uncheck this box. One thing you will notice is once you do this the editor for pixel dimensions is no longer editable, for this purpose this is a good thing.


To see how this will reproduce at a nice photo quality 300 dpi we will enter 300 in the Resolution box. 17.707″x9.96″ not a bad size! However, we will want to frame this photograph and that is of course not a standard frame size. Luckily we can work with the crop tool to get our photo to a more standard size.


Since we know that 17.707″x9.96″ is what our photo can be resized to with the same pixel ratio we will select a standard 10″x8″ for our size as that is a easily (and cheaply) attainable frame from any discount retail store.  However, a 17×10 over-sized image can produce striking results!  Printing on Poster Paper would be an ideal application!

Crop Tool

First we select our crop tool by pressing the “C” key. In previous versions of Photoshop the process herein was very intuitive, we would just insert our width and height in the top toolbar dialog while leaving our resolution blank. Later versions of Photoshop (CS6 is used as an example here) made this a little more complex than it needs to be in my humble opinion.

For these later versions we will have to select from our drop down menu and select “Size & Resolution…”. In this dialog we will enter our size of 10 for the width and 8 for the height. once we press ok we will see that our crop box has locked to a 10×8 proportion and we must compose our image for cropping accordingly.




Once done we double check with our image size to see that our photo is 373.6 dpi. so more than enough for a good quality output!



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Straighten a Photo in Photoshop – The Easy Way

We will look at a quick and easy way to straighten your photos in Photoshop.

We are all human and sometimes even the best of us have to account for a slight margin of error. Unless you shoot photos exclusively with a tri-pod or have a robot to place your items perfectly on a scanner, sometimes you need a slight bit of correction. You might even want to scan your artwork slightly crooked for a discerning technique. For whatever reason you have, Photoshop makes the process of leveling them out easy as 1-2-3.

First let us start with our example photo. I have taken the liberty of making this picture overly rotated. Yikes that needs a good straightening!

A very Crooked Photo

A very crooked photograph

The first thing we will want to do is select our ruler tool from the tool bar. You can access this on a fly out menu on the Eyedropper tool by clicking and holding till the fly out appears, or alternately you can cycle the tools by pressing Shift+I (this will cycle through all the tools under the Eyedropper)

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Now that we have our Ruler Tool at the ready we need to find a good straight edge to use. For this example I chose the edge of the door as we know that that point is supposed to be straight. Alternatively we could have used where the bricks met the door. Either will work, we just need a line that will be perfectly horizontal or vertical.


At this point we have to choices on how to proceed. We can use the Rotation Menu or the Options Bar. What one you use would be determined on if you would like to rotate all your layers and increase the canvas size to the edge of your photo or a single layer while not altering the canvas size.

Rotation Menu – Rotate All Layers And Increase The Canvas Size

From the File Menu at the top of the screen choose Image>Image Rotation>Arbitrary…


this will bring up the Arbitrary Rotation dialog however you will notice that values have already been placed inside. The Angle will have values and the Clockwise or Counter Clockwise button will already be chosen based of the angle we measured from the Ruler Tool.

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This will rotate the whole image area and add to the canvas size. This will rotate any additional Layers you have in this job

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Options Bar – Single Layer While Not Altering The Canvas Size

On the options bar while you have the Ruler Tool selected you will notice a button labeled Straighten Layer.


Clicking this button will rotate the active layer or if the image is on the background it will convert it to a single layer.

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The canvas size will not be altered in any way. If you would like to expand the canvas area to the edges of the cropped photo you can always use Reveal All located in the File Menu under Image>Reveal All

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At this point you may want to crop or re-position your photo or scan to suit your needs.


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