I don't want to store images in the cloud. In photos on my iPad, all images resolution is apparently lowered to 72 dpi. If i export photo's from the ipad to a blog for instance, this export is at 72 dpi. How do I export my full HD version?
iPad 2, iOS 9
The DPI is just a number. It doesn't change the sharpness of the image UNLESS it is used to change the size an image is displayed at - or it is used when exporting an image at a particular size to reduce the number of pixels.
So - if your image is 3000x2000 pixels, it can be exported at 5dpi - which would mean a size of 600x400 inches, and at that size would be very low resolution. But that only matters in your blog if your blog shows it at 600x400 inches - which clearly it doesn't unless your viewers have insanely large monitors.
Similarly with the 72dpi you are getting - that would mean the 3K by 2K image should be 41 inches by 27 inches - also not shown on your blog.
So if you upload that image to your blog, and your blog shows it at (say 6inches x 4inches) on the screen, then the actual resolution is 500dpi - regardless of what the dpi setting is in the file.
So the only things that impact the quality are the actual size of the image in pixels, and the actual size it is displayed at. The DPI setting is just a number that tells a printer how big to print it, and it is usually ignored.
I've just saved a file from my phone to iCloud files. It was saved at full image and file size. So photos is not the problem. You could try this on your ipad (select share, then scroll down to the "save to files"). I guess you can upload it to blogger from the files location also. I suspect that when you do, blogger will reduce the file size again.
Here is an example - an image exported from photos on my Mac at a size of 2000x2667. Resolution shown in the exif is 72x72. When I upload it here, it is displayed at aprox 9x12 on my monitor: so about 222 dpi - which is higher than the resolution of the monitor so more than is needed.
In fact the same thing happens here. If I right click and download the image I posted above, it saves at about 500MB. But the one I uploaded is 3.7MB
Because screen display only needs very low resolution images (due to the low resolution of computer displays) very often these sites reduce the image size to get one image pixel = one screen pixel.
I am guessing that is what is happening on Blogger.
Thanks again Tony. It may well be that the problem is mostly with Blogger. I did notice that upon uploading images out of Photos to Blogger, you have the option to display an image small, medium, large or original size, and the file size recorded there as 'original size' is extremely low, indeed too low for a sharp display of any moderate height or width on a blog image. However when I chose this option for display, the image is o.k. and the blur gone.
I now use this option so the Boller problem is solved. But it seems strange to me that the file size mentioned in Blogger, and possibly when exporting to other apps or to email, seems to be not the real size.
Dont look at the DPI, look at the pixels - X x Y. This is what defines the image quality. DPI Just converts that to a size.
OK - a 25M file must be a raw file, or possibly uncompressed TIF. That will be how the images are stored within the library.
Exports from photos will always be converted to compressed jpg or png - but even then, 250K is a little small. At full resolution I'd be expecting something in the 2MB to 8MB range.
How are you exporting? And how/where are you seeing the file size of 250K.
See also here:
https://support.google.com/blogger/answer/41641?hl=en
Images uploaded to Blogger may be compressed and optimized for the web, which results in less data usage and faster load times for readers. These images will not count against your Google storage quota. Currently there’s no way to store large images in original quality on Blogger.
It may be that the blogger platform is reducing your image sizes.
The larger the file size, the larger the image can be displayed at a given, let's say 150 dpi, resolution.
Not true. In the case of Jpegs all it means is that less compression has been used in creating the file. The dpi has no role in how large an image is displayed. DPI is a printing measure. You can't have dots per inches if you don't have inches, and screens don't have inches. If you display a 150 dpi image on a screen that is 72 dpi all you get to see is the effect of... 72 dpi.
What matters most in the perceived quality of an image on screen is sharpness. A sharp image on a soft screen will look soft. A soft image on every screen will look soft. The only part you have control over is the sharpness of the image.
Thanks for your help. My images are vector paintings. It is only when I export them from the vector environment that they are transformed to raster and dpi becomes relevant. Screens do indeed have their own dpi, and obviously this can be a limiting factor in how sharp the image will be displayed. No image can be displayed at a dpi above that of the screen. However, screens nowadays tend to have a dpi significantly above 72. If you use 72 dpi for display at a screen with a much higher resolution, the image will look blurred because there are empty pixels. Images displayed on any screen always have a chosen height and width, and /given the file size/ these two measures determine the sharpness or dpi of the image, IF the screen resolution is indeed sufficiently high to represent all the pixels that are offered.
The problem seems to be that google photos in iPad lowers the file size of the images, with great loss of flexibility in choosing the height, width and dpi of their display.
Could it be that your image was taken as a screenshot and that the resolution of your screen would determine its size.
1:1 for an image pixel to a screen pixel would make me very happy, in fact, that was exactly what I was looking for. It is true that printing requires a higher resolution than display on a screen, the difference is still very large, but narrowing. For printing 300 dpi is the minimum while screens used to be only 72 dpi. But screen resolution is getting higher quickly. It seems Blogger does auto lower the resolution of the initial image display to 72 dpi. The resolution of my iPad is higher and so the images look blurry.
Thanks again, I think the Blogger issue has been solved.
Thanks for your help. The size of the image is not really important to me. I do not care about a small or a large image but a sharp image is very important. So what is important to me is the pixel /density/, or dots per inch. The dpi should at least be 150-200. That is how I made them. Where are the original hr image stored and how can I use them?
When I upload images to my blog, or send by mail, all my images are apparently downsized and very small. So small in fact that I can't make use of them at all. I make use of Google Blogger to show my paintings. A blurry vector painting looks very ugly and unprofessional.
Thanks again. I fully understand that pixel density is dependent on the size that is used to display the image, and that for a given image, the larger the display size, the lower the density.
let's simplify things by talking about file size. The larger the file size, the larger the image can be displayed at a given, let's say 150 dpi, resolution.
If I create an image, I make a considered choice for /both/ size /and/ density. I cannot find these pictures back in IPad photos. Instead, file sizes seem to be strongly reduced. An image of 25M, for example, is downsized to 250k at export from iPad photos.
Downsizing severely reduces options for a sharp display, even to the point that I cannot use the image at all. My question is: where are the large image files stored that I have made?
Thanks again
I exported as .jpg and .png out of different programs, to Ipad photos, with the same result. The result is the same when I make a screenshot. I see the low size of the files when sending them by email or importing them in Blogger.
No - it would be the same if you exported just to files on your ipad.
Though it might be related to how you are getting your images onto your ipad in the first place - how are you doing that? I think if you sync folders from a mac to a mobile device you only get reduced resolution on the mobile device.
IPad: How to export images at full resolution from photo's
