Hi JustGeorge,
Definitely helpful comments, as I vary my workflow much as you appear to do, using different plugins for different situations. Without going back over each image it's difficult to know just what I have done to which image and with what! I usually do my raw development in DxO v5 and use Nik and/or On1 plugins for other overall fine tuning; compositing work I do in Affinity. I suppose it is too much to expect every developer to test their products against others to ensure that they play nicely with each other!
Much as you already have, I am learning what workarounds work in particular circumstances; a pain in the neck, but it keeps me out of mischief.
Thank you again for your comments.

Mike, as a final remark, and to exhaust the permutations that I can think of, I saved my Affinity Photo native files as 8 bit instead of 16 bit .TIFF files, as I will not be doing any more processing. These saved correctly and were accepted with no problem by QIU. The prints between bit depths show no discernible difference to my (ageing) eyes.
Regards
Andrew Turner

Reloaded the Affinity Photo v2 native format (.afphoto) and saved as .tiff with no modifications (16 bit); same corrupt result. Loaded the "corrupt" tiff file and resaved as tiff with no mods. This worked in that the image appeared, but the colour profile was not as intended, so not ideal.
At least with your help we have established that the culprit seems to be the save function. Will have to contact Serif to see what is going on. JPG's all save correctly.
Regards
Andrew Turner

Thanks for that, Mike. Hmmm - both files are composites most likely created or modified with Affinity Photo, so I'll go back to the drawing board, follow your approach and save them with no mods.
Thanks

Hi Mike,
Thanks for your prompt reply - I'm attaching a link to my DropBox that contains two of the errant files for your inspection. I hope they reveal what is causing the reading blip!

https://www.dropbox.com/sh/1sm6l74arckk5k3/AAAB3IqgnIyFsDZrQ3i8sE3ma?dl=0

Thanks again
Andrew Turner

Good afternoon Mike.
I know that this topic has been exhaustively explored in other threads, most of which I have read and tested the suggested solutions. Nevertheless, I still get the "Image read error" thumbnail on middling to large tiff files (>120Mb - 1.3Gb).
I have tried saving the files as .tiff and .tif, with no, LZW and zip compression - no joy.
I have deleted the files from my print folder and then reloaded them - no joy.
I have exported the files from: a) Affinity Photo v1 & v2, b) On1 Photo Raw 2022 & 2023, c) DxO v5 and from my DAM, Photo Supreme v7 - all to no avail.
I can print the images from the native processing apps, and all thumbnails appear in glorious Tehnicolor (or B&W) when viewed on different viewers, with the exception of FastRawViewer that also shows "corrupt" files.
This is a recent phenomenon for me, as I have been using QIU for years with no major problems; I am presently on v2023.104 and update regularly whenever they become available.
My system is Win 11 Pro build 22621 running on an 11th gen Intel core I7-11700K. I have 32Gb installed memory and a NVIDIA Geforce GTX 1660 graphics card with 24Gb memory.
I'm not sure when this error started rearing its ugly head, but I cannot recall it happening when on Windows 10. I upgraded to Win 11 about a year ago.
I'll appreciate whatever guidance you can give to overcome this glitch.
Many thanks,
Andrew Turner

Mike, thank you. I have downloaded and installed v.112 and it works very well, having recognised all my errant images. That is a great relief, so once again, thanks for your very quick and effective help. 

Thanks for your input, Terry. Any image I save as a tiff using On1 Photo Raw 2022 is not read correctly by QIU, although other apps render the image correctly - e.g. Irfanview. I tested your re-saving workaround, but to do it for umpteen images becomes a chore. I wonder whether having quite a few adjustments and effects applied to the image has an effect upon the output file? I have found no way to "flatten" the image in On1 that might render the tiff without any glitches. It would be nice to have a simple solution!

Oops, my bad; sorry about posting to the wrong forum. I am using the latest version of QIU that I updated a couple of days ago. I'm attaching a share link to one of the images I refer to. The image is located on my NAS and is good for 7 days. Hope that this works and you can access it; if it does not open directly, then perhaps cutting an pasting the link in a browser should. Many thanks. Andrew Turner.

http://AATurner.myqnapcloud.com:8080/share.cgi?ssid=8f3655e930c54adaa44976738768de89

Good evening all.

I have just updated On1 Photo Raw to v 2022. It appears that QIU is unhappy with the images exported as tiff from the referenced app and only shows either a black thumbnail or an Image Read Error as a thumbnail. If I export the images as jpeg's, QIU "sees" them correctly. All the tiff images exported from On1 2022 can be viewed correctly in other apps, e.g. DxO PL 5, Affinity Photo and Widows Photo. I am not a PS or LR user. The tiff exports are compressed using LZW.

My system has 32Gb ram, is running Win 11 with an Intel I7 11700 cpu. My graphics card is an Nvidia Geforce 1660 with 16 Gb ram.

I will really appreciate some guidance in resolving this issue. Many thanks. Andrew Turner

Thanks for sending me the D800 nef file of the black truck; reason I took so long in responding is that I thought that the file might be spam and sent it to the trash can. I retrieved it and opened it without difficulty; there seems to be no difference that I can tell between my files and this one. All my files open normally in PS CS6 ACR 7.1 as well as my working copy of the now extinct LightZone, so I am perplexed as to why I'm having difficulty with some files in QU (I am using the latest version). Perhaps I should just wait for DCRaw to be updated, as printing with QU isn't an issue, just using the image editor.

Andrew

Don't overlook the often ignored prime lenses - sharp as a tack and much cheaper than the equivalent quality zoom. In addition, every prime lens comes equipped with an organic zoom mechanism - your legs.

Using both a D700 and a D800 I will comment as follows:
For prints up to A3 my D700 (12Mp) is brilliant. For prints at A2 and above the D800 comes into its own.
I strongly endorse the comment regarding the quality of the lens; an excellent lens on 12Mp trumps an average lens on 36Mp, regardless of the size of the print. Photographic technique also plays an important part in the race for quality, and more pixels is more unforgiving - a blurry hand held picture is just as much rubbish taken with 36Mp as with 12 Mp (unless the blur is rendered with artistic intent). Good technique is essential when using high megapixel count.
One advantage of the high pixel count (when used in conjunction with good glass etc.) is the ability to crop more aggresively; you can almost do away with using the camera in portrait format and just crop the landscape one to suit.

Something quirky going on here. I ran another test with 9 NEF images and ingested them with QIU, bypassing my usual process with IDImager. Result was images ingested reasonably quickly (at least as fast as IDI but with no metatagging and keywording) and thumbs and cache produced at a rate of about 2'' per image; i'd say that that is ok. However, the NEF files could still not be read by image editor - same outcome as earlier.

Next I converted the 9 NEF images to tiffs. Some converted successfully while others just produced a blank image and thumb. Those NEFs that successfully converted to tiffs would now open correctly in the image editor (as well as the TIFFs); those that produced blank TIFFs would still not open in the image editor.

Any ideas why this might be? Many thanks.

One more thing. The image editor part of the software does not like my NEF files; if I double click on a thumb I either get an "image read error" or a blank screen. Dragging and dropping a thumb onto the print window produces the required image and the photo prints ok. Does this mean that DCRaw has not yet been updated for the Nikon D800?