Shabbat 80A

תנא: שתי אותיות בדיו, שתי אותיות בקולמוס, שתי אותיות בקלמרין. בעי רבא: אות אחת בדיו, אות אחת בקולמוס, אות אחת בקלמרין, מהו? תיקו.

A tanna taught in a Tosefta: The measure that determines liability for carrying out ink is equivalent to that which is used to write two letters when he carries out dried ink, and two letters when the ink is in the quill, and two letters in the inkwell [kalmarin]. Rava raised a dilemma: What is the halakha if one carried out sufficient ink to write one letter in the form of dried ink, and sufficient ink to write one letter in the quill, and sufficient ink to write one letter in the inkwell? Do they join together to constitute the measure for liability, or is each considered separately? No resolution was found for this dilemma. Therefore, let it stand unresolved.

אמר רבא: הוציא שתי אותיות וכתבן כשהוא מהלך ⁠— חייב, כתיבתן זו היא הנחתן. ואמר רבא: הוציא אות אחת וכתבה, וחזר והוציא אות אחת וכתבה ⁠— פטור. מאי טעמא? בעידנא דאפקה לבתרייתא, חסר ליה שיעורא דקמייתא.

Rava said: One who carried out a measure of ink equivalent to that which is used to write two letters on Shabbat, and he wrote two letters as he walked, even though he did not place the written material in the public domain, he is liable for carrying out the ink. Their writing is their placement. He is liable even without placing the ink on the ground. And Rava said: One who carried out sufficient ink to write one letter and he wrote it, and then proceeded to carry out sufficient ink to write one more letter and he wrote it, is exempt. What is the reason that he is exempt? At the time that he carried out the last drop of ink, he was lacking the first measure of ink. The ink that he carried out first dried slightly in the interim and not enough remained to write one letter.