I am very pleased and wish you a lot of perseverance. I have already started to prepare my personal "look out the window". In the summer I would like to start. Many greetings Przemek

@@przemek.zajfert Thank you for your kind reply. I am very patient - and do not give up when I have a goal! Have you written any books or papers on heliography? I do not want to bother you with hundreds of questions! Stay safe and happy in your part of the world. Bradleigh 🐧

@@TheStockwell Unfortunately, have not written any papers on heliography. Niépce describes the technique in 1929: gallica.bnf.fr/ark:/12148/btv1b8593641q/f5.image. I have experimented a lot and also tried a lot. It is simply exciting to rediscover such an old photographic technique.

@@przemek.zajfert I just saw your reply. Thank you! Nicéphore Niépce's own handwritten notes - astounding! My wife can translate them. I have found places to obtain the asphalt, lavender oil, and turpentine. Now, all I need is precise instructions on measurements and mixing - and days and days of sunlight. Good news: my research shows that a day on the planet Venus lasts 243 Earth days. A perfect place to make heliographs! 😸

Very nice. Could i use this method to engrave the steel by electro etching??

Bitumen of judae mixed with water then an alloy sheet was coated with it and was heated and etch with the picture then exposed to light for more than 8hours don't know about the solution used to wash it later though maybe petrolleum

Thank you. I have good results with aluminium sheet, copper and also tinplate. I still want to try with brass sheet because of the yellowish colour.

Thank you. Maybe better with turpentine, for example citrus turpentine or other types of turpentine. They are much cheaper than lavender oil. I sometimes use gasoline at the very end of processes for a quick wash. Niepce used running warm water, but it didn't always work for me.

The oil only takes a certain amount from the asphalt. You can also use more lavender oil; the longer you leave it on, the darker the varnish will become. For camera exposures, I coat a very light varnish to achieve the positive-negative effect. However, it's always a coincidence, and you can't really predict it

@@przemek.zajfert thanks for your reply. I realized I was wrong in assuming a larger volume was necessary. I was basing that on a different formulation I’ve been using where I dissolve 5g into 100ml solvent (I use xylene) and then dilute that further to 2.5%. You’re using a different formulation resulting in a much higher percentage solution re 3g into 15ml (16.67%). I decided to give it a try and mixed up a batch with your dilution (but still using xylene so we’ll see how that works). It’s sitting for a few days and then I will try it. I think I saw that you leave your plate exposing in sun for longer periods (a couple of days). Is that accurate? Thanks for your help.

Yes, it must be completely dry. After the exposure is developed in lavender oil or turpentine. I have also tried with petrol, it also worked

@@przemek.zajfert thanks, i will use petrol.👍

I exposed like this years ago. I got exposure times of several days (in summer). What the Internet says about 8 hours, can not be true, there the asphalt emulsion is not hard enough :)

@@przemek.zajfert You are absolutely correct, Mr. Zajfert. The eight-hour exposure time was an assumption based on speculation about the shadows in the image. A modern researcher using methods and materials described by Niepce says the exposure time for this historic image was *several days.* Blimey! 😬

Yes. 3 years ago I used an 8x10 inch camera on a very thin asphalt. It was summer. An exposure time of 70 hours gave usable results. Niepce's first photography had to be exposed for much longer than 8 hours

@@przemek.zajfert Physautotype was claimed to have shorter exposure time than Heliography, and Physautotype photo takes 8 hours to expose. Now all these statements are finally consistent with each other!

@@przemek.zajfert Ah, by the way, does your "70 hours" include nighttime, or only daytime exposure is counted?

@@sjhstone My exposure time was just 70 hours of sun. The camera was standing for about 1 week. At Physautotype makes the emulsion more sensitive and the exposure time is shorter. The first photo of Niepce (view from the window...) was not a physautotype, so the exposure time would have to be much longer than 8 hours. I speak from the experience of around 500 heliographies I have made so far.

@@przemek.zajfert Cool! Thank you very much for the information. I'm currently working on a short article about the invention of photography, and your reply really helps a lot!

The bottle probably had a leak. Just add lavender. Best regards

Hello, no I do not filter the emulsion. This year I used an emulsion that was about 5 years old. I take carefully with the brush without shaking the glass. My negatives have normal density. With denser negatives, the exposure lengthened quite a bit. I like to leave a lot of room for chance, so my working method is not very precise.

@@przemek.zajfert than you very much. I will make a new solution today. How many days do you wait when you make a new emulsion before to use it?

Until the bitum that did not dissolve is down, so 1 to 2 days

@@przemek.zajfert In your video, you put the emulsion with light and you let dry the plate on light. When i red notice of heliography of Niepce, and comments with Daguerre, they say to put the emulsion with a candle light. With your experience, does it change anything on the final photo to put and dry the emulsion on light? Thank you!

@@francosh27 The heliography process I use dates from 1822 to 1826, it is not a physautotype process, which Niépce developed with Daguerre in 1832 and the emulsion is much more sensitive than earlier methods of heliography. Unfortunately, I am not very familiar with the physautotype process. Best regards Przemek

It might be that there are other materials which work but i did not try so far. Perhaps it can work with other graphic bithum.

@@przemek.zajfert ok, thank you!👍

There are juices which bleach in UV, and might be used. You cannot fix the photo tho like here

@@butlaoctu4464 thanks!

@@albertovitali5610 There's also physautotype, just rosin in alcohol, you probably already heard about it.

You can also use other devices

Probably it will be faster. On paper also goes, but it comes very blunt.

yes. it will take several days to expose, though

I tried that with Glass. Unfortunately, the results were not so good. It lacked the brilliance of the polished sheet metal.

@@przemek.zajfert would doing it with normal mirror change anything?

It doesn't seem like the best idea since there's some space between the reflection and the image but idk, I'm no physicist nor do I have talent in making light simulations in my head lol

@@butlaoctu4464 Probably. I would test it.

@@butlaoctu4464 I think you should do like Niepce did...just test and play with the medium.