Intermediate Tutorial 12
With the many varied ways digital images are used today – from social network sharing to displaying on tablets or digital photo frames (or even as prints!) – it is worth planning certain aspects in advance. Here, we examine the choices you must make for your photographs in terms of size and shape, file size and resolution.
Displaying, Printing & Aspect Ratio
Making best use of your digital photos
From illustrating a web site, uploading to social networks and photo sharing sites – such as the LUMIX G Experience – to displaying in digital photo frames, on laptops, tablets or TVs and even – yes, some people still do! – creating prints, today’s useage of digital photos is so varied. So, when you know how you plan to use your photographs, the main factors to consider are file size and resolution. Although completely different, each affects the other and ignoring their attributes could cause you problems later on.
Photos for web use
When taking photos for online use, including if you have your own website, the resolution need not be as high as for printing – because they usually appear quite small and a computer screen’s resolution enables viewing without noticing too many imperfections. The lower the resolution, the smaller the file size – and smaller files are often preferred by web hosts, because they enable faster page loading. Indeed, some hosting sites specify a max. resolution or file size.
As a general rule for web use, images should be 72ppi (pixels per inch) density, so an 8×6” photo on-screen only requires 576 x 432 pixels – just under a quarter of a million. Of course, if your camera could take such low-res images, it would not capture much detail; you actually need a lot more pixels in images to start with. A 4 megapixel image (probably your camera’s lowest setting) usually suffices.
Photos for TV or photo frame slideshows
As with computers, TV screens and digital photo frames display images at much lower resolution than the original. HD TV screens usually contain 1920 x 1080 pixels and photo frames fewer still – but both are capable of resizing any photo (within resolution limits) for display.
However, you may find the resizing process slows down the slideshow, causing inconvenient delays between pictures. To avoid this, resize your photos in-camera (or with photo handling software), most models have a ‘Resize’ option to convert/shrink images, usually including the option to save the resized image as a new file, as shown here on the LUMIX G6:
Another thing to consider when preparing a slideshow is aspect ratio. For pictures to display full-screen, you may need to crop them to match the aspect of the display – modern TVs are 16:9 (widescreen); digital frames can be either 16:9 or 4:3 aspect ratio. So, plan beforehand by setting the camera to shoot in the correct aspect, or crop afterwards on your computer. Then, save the images back onto a spare SD card or USB memory stick for insertion into your chosen display device.
Photos for printing
Resolution and aspect ratio are also the main considerations when planning to print photos. It’s easy to think that for the best quality prints, you should set the camera to its highest resolution – in fact, high-quality prints can be obtained from resolutions much lower than you might think. The requirement is based on a density of 300dpi (dots per inch) – not the same as ppi, but for our purposes we will equate them.
Once we know the ppi needed for a good quality print, simple maths tells us how many megapixels are needed for different sizes of photo paper:
|4×6”||@ 300ppi = 1200 x 1800 = 2.16MP|
|5×7”||@ 300ppi = 1500 x 2100 = 3.15MP|
|8×10”||@ 300ppi = 2400 x 3000 = 7.20MP|
|8.25×11.75” (A4)||@ 300ppi = 2475 x 3525 = 8.72MP|
|11.75×16.5” (A3)||@ 300ppi = 2475 x 4950 = 12.25MP|
Evidently, most modern cameras (12MP+) can produce images that will print up to A3. But don’t forget you may want to crop your originals – this could reduce the pixel count by as much as half!
The industry recommendation may be 300dpi/ppi for the highest print quality, but as cameras generally don’t record at such high pixel density, you might need a little skill with a software package* to convert them to the resolution the printer requests – bear in mind some companies are happy with 200 or even 180ppi.
Although, even if you print photos as they come, direct from the camera/memory card, you should still get great results. And using a photo printer at home may be more cost effective.
* Using Photo software is a topic for a whole new tutorial which unfortunately will have to wait for another day.
How aspect ratio affects printing
The final thing to consider is how the shooting aspect affects how the images will look on photo paper. The aspect ratio dictates the height and width of photographs, each option offering a different shape and pixel count. The four most common ratios are 4:3, 3:2, 16:9 and 1:1. Let’s look at each in turn, as some aspects are more suitable for prints than others.
Your printer settings or software will normally offer a choice of image-to-paper fit:
- Page fit – the image is cropped, to use the full size of the paper
- 1 to 1 fit – it is not cropped, but may leave a border on the paper
4:3 images, using ‘page fit’ – with dotted lines showing the image cropping
4:3 images, using ‘1 to 1 fit’, borders may appear
3:2 images, page fit
3:2 images, 1 to 1 fit
16:9 images, page fit
16:9 images, 1 to 1 fit
For perfect printing of 16:9 aspect images with no cropping and no borders use special 16:9 wide photo paper 18.1 x 10.2cm.
1:1 images, page fit
1:1 images, 1 to 1 fit
So, now you have completed this intermediate module, hopefully you have learned there are many things to consider when you go out shooting with your camera, but don’t worry, the more you put what you have learned into practice, the easier it becomes and very soon it will all be second nature to you.
Above all remember that photography should be fun, so enjoy it.
The LUMIX Advantage
Where cameras traditionally record images at 72ppi density, all LUMIX G models create JPEGs with 180ppi, for display or print purposes – meaning that when printing them yourself or sending off to a printer, you may not need to change the ‘PPI’ setting in your software.
Try all your camera’s resizing options – take a few images at the highest resolution and resize them in-camera to the different options, saving them as new pictures (preserving the originals). Check them at home on your computer or print them out, to look for differences in quality.
Not sure what something means? Read our glossary