HP-35: Clean images

[sasa]

I'm in the process of polishing my own HP-35 emulator before publish (freeware).

However, since I do not have the real calculator, I'm trying to find proper images on the web. Unfortunately, I'm unable to find clean, with in proper angle and higher resolution (at least 1000px for vertical size), including all display digits and signs images.

I hope some collector with the HP-35 in good shape is willing to make a few shots and share them here.

Thanks in advance.

[rprosperi]

(08-17-2018 01:14 PM)sasa Wrote:  I'm in the process of polishing my own HP-35 emulator before publish (freeware).

However, since I do not have the real calculator, i'm trying to fine proper images on the web. Unfortunately, I'm unable to find clean, with in proper angle and higher resolution (at least 1000px for vertical size), including all display digits and signs images.

I hope some collector with the HP-35 in good shape is willing to make a few shots and share them here.

Thanks in advance.

Eric Rechlin, creator of hpcalc.org, has generously made some excellent torrent files available, including one which has hi-res photos of almost all HP models. The HP-35 photo listed is nearly 600 KB, so obviously high quality, and probably suitable for the overall machine image.

The torrents can be found here: https://www.hpcalc.org/torrents/#

[Gerson W. Barbosa]

 
Better photographer, better camera and better calculator still required. Anyway, just to show off mine :-)

[striegel]

Reasonably good results can be attained by laying the calculator, face-down of course, on a flatbed scanner. It may take some experimentation to find the best angle to use for the proper lighting effect.

I should also warn that scanning will emphasize every tiny speck of dust, so it requires a very thorough cleaning of the calculator and the scanner's glass. You may be able to tell which of my calculator images are scans in the Flickr album. (I hope that link works correctly.)

Sorry that I don't have an HP-35 of my own.

Alan

[AndiGer]

Gerson, very clean calculator. What did you use for restoring it?

[Gerson W. Barbosa]

(08-17-2018 07:51 PM)AndiGer Wrote:  Gerson, very clean calculator. What did you use for restoring it?

Nothing. I bought it about 12 years ago from someone in Tasmania. There is a minor wear in the golden trim, next to the ON/OFF switch. I cannot tell if it ever has undergone any restoration, though.

The old picture here was taken under daylight.

[Gerson W. Barbosa]

(08-17-2018 06:21 PM)striegel Wrote:  Reasonably good results can be attained by laying the calculator, face-down of course, on a flatbed scanner.

Thanks for the tip, but very poor results so far on my DeskJet 3636. Perhaps the scanner is not good enough or I just don’t know how to use it.

Gerson.

[sasa]

Gerson,

Thank you very much. I can say the same, very clean specimen, If I do not know it is more than 45 years old, I would say it is brand new...

Yes, in a daylight would be much better image. The light should be from the left or right to avoid shadow under buttons as they are quite high for HP-35 (perhaps 5mm, or even more). That is the reason scanning will not give good result here, as with low profile button calculators shown here as well (thank you, striegel ).

If you may take several shots in a daylight, I do not think better can be done:

1. To avoid jpeg quality image degradation, shot image with the higher quality settings for jpg (less compression), or set png, raw or any other lossless format camera may support. The best result may be done if you have a small tripod for camera, as several shots are needed in fixed camera position.

2. One shot when calculator is off. Needed for proper on/off slider position and display off look.
3. Another shot when calculator is on. Display should show '0'. If some backlight comes from cathode tubes when calculator is turned on for unused cathode tubes.
4. Another shot when calculator is on. Display should show "1.23456789 - 01"

Nothing else is needed, perhaps back side as well with the guide, however that is not essential...

From these images proper bands and digits are cut down and used. Of course, if you do not have a tripod, you may make these shots freely from hand and then I can correct all additionally (proportion and position), as well as a minor wear.

You may upload it on your page, if forum limit for attachments is reached.

Thank you very much!

[John Keith]

Another issue with photographing LED calculators is that the LEDs tend to wash out or bloom because they are much brighter than the rest of the calculator. If you have the camera mounted on a tripod you can take one properly exposed photo, and one photo 2 or 3 stops darker to properly expose the LEDs, and combine them in Photoshop or similar.

John

[Kees Bouw]

(08-17-2018 09:21 PM)Gerson W. Barbosa Wrote:  

(08-17-2018 07:51 PM)AndiGer Wrote:  Gerson, very clean calculator. What did you use for restoring it?

Nothing. I bought it about 12 years ago from someone in Tasmania. There is a minor wear in the golden trim, next to the ON/OFF switch. I cannot tell if it ever has undergone any restoration, though.

The old picture here was taken under daylight.

Was the HP-35 ever produced with a gold trim? I always thought that they were all produced with a silver trim, and that the gold trim that you sometimes see was done afterwards to repair a worn silver trim. Perhaps because a gold leaf pen was available or because the owner liked gold better than silver.

Kees.

[sasa]

(08-18-2018 01:12 PM)Kees Bouw Wrote:  Was the HP-35 ever produced with a gold trim?

According to Nigel Tout's page (http://www.vintagecalculators.com/html/t...lator.html), only some prototypes had golden trim. Of course, owner may have any correction which prefer. On Gerson's page, on older daylight picture, seems it shows silver trim.

One another obvious effect is that under different light and exposure, digital camera tends to distort colors.

[Gerson W. Barbosa]

(08-18-2018 07:16 AM)sasa Wrote:  If you may take several shots in a daylight, I do not think better can be done:

Too cloudy here today for outdoor shots, so this will have to wait a while. I have a tripod, but I can’t attach my smartphone to it (that’s what I used for the most recent picture). Another option is my old 5.1 megapixel Cyber-shot picture (DSC-P93). I ‘ll see what will be better.

[sasa]

(08-18-2018 04:39 PM)Gerson W. Barbosa Wrote:  Too cloudy here today for outdoor shots, so this will have to wait a while.

Gerson,

Please take your time. Whenever you are willing and weather allow...

Thank you very much again.

[Dieter]

(08-17-2018 09:30 PM)Gerson W. Barbosa Wrote:  

(08-17-2018 06:21 PM)striegel Wrote:  Reasonably good results can be attained by laying the calculator, face-down of course, on a flatbed scanner.

Thanks for the tip, but very poor results so far on my DeskJet 3636. Perhaps the scanner is not good enough or I just don’t know how to use it.

Using a scanner for such things indeed may work very well – if (!) it's a conventional CCD scanner.

There are two common types of flatbed scanners: CCD and CIS. The former offers good depth of field which is crucial for copying three dimensional objects. Your Deskjet 3636 multifunction device includes a CIS scanner – which is the technique used in most of today's very flat scanner models. But these provide virtually no depth of field at all, which means that they work fine for flat objects but nor for anything else. You may take a look at this website to see the difference. Please also note the link to a page with slide rule pictures generated with a CCD scanner.

However, your HP35 picture can be improved. Please do not use a wide angle lens (or a cell phone) for this kind of pictures. Since you are very close to the subject the lens sees some parts of it from below and others from above (take a look at the upper and lower key rows). What you need is a larger distance – and therefore a moderate telephoto lens. If you got an old Sony P93 set it to the longest telephoto setting and carefully align the camera exactly (!) vertical to the calculator surface.

Dieter

[sasa]

(08-18-2018 08:57 PM)Dieter Wrote:  Using a scanner for such things indeed may work very well – if (!) it's a conventional CCD scanner.

I still have an old CCD scanner I use even today (HP ScanJet 4400c), which wasn't cheap at all when bought brand new long time ago.

The main problem is that inside is not sealed properly and dust is not just outside the glass, but as well inside, which is not possible to clean up without full disassembling. The second problem is that flat cable inside is dragged out while scanning and make quite visible traces on glass. Similar with the whole lamp and CCD module, leaving easily visible vertical traces. (part of the calculator scan image).

As well, light is so bright (and under angle) that shadow is easily visible (LR44/AG13 button cells scans, which are about the same height as HP-35 button). Not even that, there is quite visible chromatic aberration.

Perhaps these problems are not existed with modern CCD scanners.

EDIT: it is ScanJet, of course, not LaserJet...

[Gerson W. Barbosa]

(08-18-2018 10:50 PM)sasa Wrote:  I still have an old CCD scanner I use even today (HP LaserJet 4400c), which wasn't cheap at all when bought brand new long time ago.

Too bad my ScanJet 4c doesn’t work anymore (SCSI interface, no more drivers). That was a scanner!

You’ve got PM.

[Dieter]

(08-18-2018 11:07 PM)Gerson W. Barbosa Wrote:  Too bad my ScanJet 4c doesn’t work anymore (SCSI interface, no more drivers). That was a scanner!

Maybe you can use a CCD scanner somewhere else. Everything that doesn't look like today's common fancy flat ones has a good chance of being a CCD device. A "scanography" is the first thing I would try here, too. Try different orientations and place the calculator upside down on the scanner. This way you can get a scan where the shadows of the keys are below them, which looks much better than a shadow above the keys as seen in many scanner generated pictures.

BTW, if the software doesn't fit the hardware, make the hardware match the software: keeping an older XP machine for such applications is not the worst idea. Some time ago a friend of mine sold a complete scanning setup (including an old Nikon LS-10 SCSI film scanner*) to a happy new owner. ;-)

Dieter

*) Yes, there are other ways to get an LS-10 running under a current OS.

[Dave Shaffer]

(08-18-2018 04:39 PM)Gerson W. Barbosa Wrote:  

(08-18-2018 07:16 AM)sasa Wrote:  If you may take several shots in a daylight, I do not think better can be done:

Too cloudy here today for outdoor shots, so this will have to wait a while. I have a tripod, but I can’t attach my smartphone to it (that’s what I used for the most recent picture). Another option is my old 5.1 megapixel Cyber-shot picture (DSC-P93). I ‘ll see what will be better.

Actually, a cloudy day is GREAT for photographing something like a calculator - the light is about as uniform as you can get. Just make sure you have the white balance correct.

[striegel]

(08-18-2018 08:57 PM)Dieter Wrote:  ...
Using a scanner for such things indeed may work very well – if (!) it's a conventional CCD scanner.

There are two common types of flatbed scanners: CCD and CIS. The former offers good depth of field which is crucial for copying three dimensional objects. Your Deskjet 3636 multifunction device includes a CIS scanner – which is the technique used in most of today's very flat scanner models. But these provide virtually no depth of field at all...
Dieter

I have to express my thanks to Dieter for the range of things I learn from his posts here. Until now, I've been taking for granted the excellent depth of field of my old HP PSC 950 (around 18.5 mm by my measurements), which has served well for scanning watches and calculators. I didn't realize there was such a range before this.

Alan